Virus Breeder

Virus Breeder is a machine in Mega Man Battle Network 3, created with the intent of studying various virus species. During the game, Lan Hikari and MegaMan.EXE are asked to round up viruses and send them to the Virus Breeder as a side quest. While some viruses are gotten by different means, most are found when MegaMan walks onto a certain place on the net, resulting in a battle with all versions of that particular virus. When defeated, they will stand idle in front of MegaMan, where he sends them to the Virus Breeder. By returning to the breeder, Lan can receive a chip that summons that species of virus, cycling through the different versions before being summoned with the A button.

Once the game is beaten and certain requirements are met, the Ω version of each species and the Scuttle viruses can be obtained.

Virus Stats
Each Mettaur attacks by sending out a shockwave travelling down the row. The Omega version's shockwave cracks panels.

Virus Stats
Once summoned, the Bunny attacks like it does in the wild, by shooting out a Zap Ring which can stun the enemy for 2–4 seconds, depending on the version summoned.

Virus Stats
Each Spikey attacks just like it does in the wild, by breathing a fire shot that travels forward down the row until it makes contact with a target. Each species has its own explosion pattern, just like in regular battles. Upon making contact, Spikey's attack is a ShotGun explosion pattern, Spikey2's is a V-Gun pattern, Spikey3's is a SideGun pattern, and SpikeyΩ's is a Spreader type pattern.

Virus Stats
Each member of the Swordy species has its own element and attack. Swordy, bearing no element, attacks with a Long Sword attack. Swordy2, a Heat element, attacks with a Fire Sword. Swordy3, an Aqua element, attacks with an Aqua Sword. Swordy Ω, having no element, and unlike its wild counterpart, attacks with a Life Sword (range 2 rows by 3 columns). Since the virus levitates, it can be summoned over a hole.

Virus Stats
All Jelly variants attack with a three row wave attack, just like in the wild. However, each variant has a different element of their wave attack. Jelly inflicts Aqua damage, HeatJelly inflicts Heat damge, EarthJelly inflicts Wood damage, and Jelly Ω inflicts Aqua damage. Although Jellys appear to hover, they cannot be summoned over a hole.

Virus Stats
Once summonded, each Mushy variant attacks by emitting spores around it, which hit all the panels surrounding the virus. However, unlike the wild variants, summoned Mushys do not require grass panels to be summoned. Upon hitting an enemy, Mushy's attack inflicts a confusion status on the enemy, lasting for a 8 seconds for Mushy, 12 seconds for Mashy, and 16 seconds for Moshy and Mushy Ω.

Virus Stats
All Momogra variants attack by hitting the target on the panel in front of it with a shovel.

Virus Stats
The KillerEye variants attack very similar to how they do in the wild; they release a paralyzing electic beam in a certain orientation, which is capable of piercing Invisible and Shield statuses. KillerEye and KillerEyeΩ's attack orientation is straight forward, down the row. DemonEye's attack is diagonally upwards. JokerEye's attack is diagonally downwards. Since the virus levitates, it can be summoned over a hole.

Virus Stats
Each Scuttle variant is very different from the others. They generally attack similar to how they do in the wild.
 * Scuttle attacks by summoning and pushing an IceCube forward down the row. This attack only hits the first target it makes contact with, dealing Aqua damage. If there is no target in the row, then the IceCube will travel past the field and disappear, unlike the wild Scuttles whose missed IceCube remains on the last available panel in the row.
 * Scutz attacks by summoning a homing FireTower, which deals Fire damage.
 * Scuttler attacks by summoning Lightning from the sky, hitting every enemy on screen dealing Electric damage.
 * Scutzer attacks with GreenRope, by summing vines which entangle all the enemies and deal Wood damage, in addition to dealing an extra 30 points of non-elemental damage for up to 4 seconds, unless the enemy breaks free of the wrap.
 * Scuttlest attacks by firing a non-elemental beam straight down the row.
 * ScuttleΩ attacks just like Scuttlest, by firing a non-elemental beam straight down the row.

Raising
By Jacking In into the Virus Breeder, MegaMan can feed each species of virus a certain amount BugFrags, which increases their attack power. However, because there are multiple versions of the same species, the Bug Frags must be distributed amongst them, leaving the player to decide which version should get the most, and in turn, which one does the most damage.

The player feeds them 5 BugFrags at a time, for a total of 100 BugFrags for virus group, to be distributed as the player decides. To distribute them the player can talk to each virus and feed them directly via their pet bowl, or by talking to a program in each cell to do so (the player must feed the viruses first before using this program to redistribute.)

Trivia

 * Virus Breeder only made an appearance in Mega Man Battle Network 3, without being implemented or ever having been mentioned in any of the subsequent Mega Man Battle Network games.
 * Taking into account all the possible chip codes for each virus chip that can be obtained through legit or hacking means, the chip letters can be arranged to spell out a word very close to the viruse's name (e.g. in case of Mettaurs, all the possible chip letters can spell out METOL).