Viruses

Viruses are the main enemies encountered in the Mega Man Battle Network series, usually unleashed upon the city by a villainous mastermind, such as Lord Wily. Viruses are found randomly across the cyberspace, searching for NetNavis and other programs to delete. A NetNavi must have basic Virus Busting abilities to navigate safely on the net, otherwise its actions will be limited. Viruses may leave Battle Chip data upon deletion. This all depends on the virus, and the attack that the virus uses. Most viruses have three variations, sometimes more.

What follows is a list of viruses from the Battle Network games. This list is incomplete.

Mega Man Battle Network[]

Mettaur
Ammonicule - it is protected by a bubble which must be popped before the player can damage it.
Beetank - when it fires its bombs, the bombs spread varying damage across the cyberfield depending on the variant's ability.
Big Snake - it takes up three panels on the cyberfield instead of one. Only its head can be damaged, and releases a SnakeEgg when its HP is halfway depleted.
Billy - this ball with eyes, feet, arms and a lighting bolt coming out of the back of its head moves around by one panel in random directions. It then releases an electric ball that floats toward the player and stuns them.
Canodumb - this virus cannot move, but attacks when the player moves into the same column it is in. In later games, it is upgraded to a CanGuard.
Cloudy - its attack consists of summoning a raining cloud moving back and forth over one column of panels. It cannot be damaged while it is jumping.
ColdBear - it remains stationary while shooting out ice cubes towards its target.
Fanner - this stationary virus produces a swirling tornado, capable of moving a set amount of panels, which homes in on the player.
Fishy - it moves up and down its column until it is on the same row as the player. Then, it charges up a little bit and dashes forward. It will pass the player twice before starting the process again.
Flappy and Powie - the Flappy hops around its area for a short while before jumping over to the player's side and becoming a weight (a Powie) that crushes down on the same square the player is standing on, cracking it in the process.
Floshell - this mechanical enemy has a shield which must be knocked upwards, exposing the virus and giving the player a chance to strike before it lowers it again. It shoots cannonballs.
Gaia - this hammer-wielding virus cannot be damaged while grey. It turns purple when it swings its hammer, and only then can it be damaged.
Handy - a Handy attacks the player by approaching through a wormhole and fastening a TimeBomb to him/her. When the TimeBomb detonates in three seconds, it sends an area-wide explosion onto the side of the field it was located.
HardHead - A stationary cannon-like virus. Before attacking, it will wobble, and its mouth will open to shoot out a cannonball. The cannonball will fly and land on the panel which the player was standing on, prior to its release. When the cannonball lands, it will break the panel it falls on.
Jelly - it slowly moves up and down the columns. After a certain amount of time, it unleashes an elemental wave attack down all three rows.
Miney - the doll-like virus produces a mine from within its mouth, goes into the ground through a black hole and randomly places a one-panel mine onto the player's side of the field, after which it reappears back on its own side.
Piranha - when it first moves to a panel, it releases a lock-on crosshair traveling forward. If there are no obstacles in the way, the virus moves onto the next panel and repeats the process. If the crosshair lands on the player, the virus shoots a metallic arrow out of its mouth.
Popper - although not visible at first, the virus drops down on a wire to attack. It attacks with homing wood towers.
Puffy - it attacks by blowing bubbles. If the bubbles make contact with the player, they cause a giant explosion, dealing massive damage.
Ratty - attacks by releasing mini versions of itself, which move very fast in a straight line.
Rush - a rare enemy that doesn't attack, and every attack done to it causes only 1 HP of damage. Rush creates three holes and appears in one of them. If the player doesn't hit it before it returns into the hole, it will escape the battle. Rush was originally designed for Mega Man Legends 2, but was cut and later used in the Battle Network series, appearing in every single one.
Spooky - this virus remains stationary, but teleports to a different panel if the player goes to the same row as it. Spooky will then vanish again and reappear on the panel in front of the player and attack by licking. This virus can also heal itself.
Swordy - a virus which can attack by up to 2-3 panels forward. It can also use AreaGrab, and steal a row of the cyberfield from the player.
Twisty and Remobit - Twisty never moves from its position in the back row, but it releases a Remobit, which continuously moves and shocks panels with electricity.
VolGear - it moves on the two panels not aligned with the player. When attacking, it opens its jaws and releases a homing fire tower.

Mega Man Battle Network 2[]

Scuttlest - improved version of the Scuttle virus introduced in the first game, itself based on the first game's boss. It attacks by firing a large laser straight ahead. A Scuttle is blue, while a Scuttlest is white.
Bunny - it will shoot an electrical ring from its ears towards its target. Upon impact, the target will be paralyzed for a short time.
Flamey - it remains still, unless the target is on the same row as it is. If this happens, it gets angry and begins to bounce down the row. While bouncing, it breaks each panel it lands on.
Lavagon - the virus appears in and out of hole panels, warping around those panels and breathing fire at its target.
Magneaker - it travels on all fours and shoots out an electric bomb from its head at its target. If the bomb hits its target, the target will be stunned for a short period of time.
Mushy - unless it lands on a grass panel, it becomes immobilized. It attacks by spreading spores around itself, moving in close to the target and emitting a cloud of them.
Protecto - always appearing with a group of other Protectos, this virus needs to be destroyed along with its group in one hit; otherwise, its HP restores back to its original amount. The virus comes with a countdown timer that starts at 10. When the timer reaches 0, the virus attacks with a field-wide explosion, dealing a total damage equal to one of the Protecto's HP.
Yort - it shoots a yo-yo out of itself, launching the yo-yo along the row which eventually comes back.

Mega Man Battle Network 3[]

AlphaBug - one of many mini versions of the final boss Alpha, this virus attempts to absorb the target.
Eleball - it moves diagonally along the cyberfield. When it is adjacent to its target, it fires an electrical attack in all directions around it.
N.O - it must be defeated fast or its HP will quickly regenerate. It attacks by sending a copy of itself towards the target in a straight line. If it lands on the target, it deals damage and paralyzes the player. When it projects a copy, it turns light-blue and has a purple X on its face. The copy is also this color.
Slimey - Slimey hops in one of four different directions, one panel at a time, changing the panel's color to its own color, stealing it away from the player.
Trumpy - this headphones-wearing horn jumps up and down, playing music that makes its allies invincible. Variants have other affects.

Mega Man Battle Network 4[]

CirKill - like its name implies, this virus moves in a circular fashion, attacking the target while it does.
Melody - a musical note which can hop up to four times on the player's side of the cyberfield before returning to its own side.
Weather - the virus lowers itself down on a wire and blows a breath, changing a panel into one of the various element types.

Mega Man Battle Network 5[]

Appley - a green worm virus that attacks by spitting seeds, converting panels into grass panels. While inside its apple, it can only be damaged with break-type attacks; otherwise, it is only vulnerable while attacking. Once defeated, Appley will restore some HP to a nearby ally.
CanGuard - an upgraded version of the Canodumb, now equipped with a shield.
Champy - a boxer virus with flaming fists, a Champy remains stationary on a panel until an enemy moves into its line of sight on the cyberfield; when this happens, Champy teleports to deliver a fiery punch.

Mega Man Battle Network 6[]

BigHat - it moves around its side of the field, throwing a flash bomb onto the player's side. This bomb may paralyze, blind, or confuse the player depending on the type of the virus.
Cragger - it attacks by throwing its fist onto the panel the target is on. On contact, the panel is cracked, along with the panels above and below it.
DarkMech - similar to a Billy, a DarkMech finds its prey by shooting out a Thunder Ball. However, only if the target is struck by it, the DarkMech attacks by warping in front of the target and slashing with a Wide Sword-style attack.
FighterPlane - it attacks by releasing gun shots, or using its propeller.
HauntedCandle - weak to water, this virus attacks by engulfing a 2x2 portion of the player's side of the field in fire. Wind-type attacks will snuff out its flame, leaving it defenseless, but a fire-based attack from either side will ignite it again.
Kettle - when hit with a fire-based attack, the temperature of this virus rises until it explodes.
Nightmare - this shadowy sword-wielding virus initially appears on the enemies' side of the field in the form of a small whirlwind and cannot be damaged. After a few seconds however, they will start moving around the player's side of the field, attacking with a Wide Sword-style attack after three moves.
Puffy - if this blowfish virus is hit, but not deleted, it will inflate and shoot out two needles. The second time it is struck, it fires three needles. Because of this, a Puffy should be deleted quickly.
PulseBulb - it moves slowly around the area. At this point, it is only vulnerable to Break type attacks. When it spots an enemy in its row, it moves forward, opens up, and launches an Elec Pulse hitting in a short, sideways T shape. It is vulnerable to attack while it is attacking.
Scarecrow - a lightning-based enemy that regains health when hit by electric attacks. It then attacks by sending a stream of electricity down the player's row. It can also hit itself with a lightning bolt to fully heal.
Shrubby - it likes to hide behind an obstacle or ally, moving up to the front row of its side to roll out a log. The logs can be destroyed by attacks.
Starfish - this stationary virus fires three bubbles which head towards the back row and then either up or down it. Targets hit by the bubbles are trapped in them for a second. The bubbles can be destroyed by attacks.