Just before you go to fight DrillMan, you'll see that the SciLab Virus Lab has a brand-new electronic wizardry machine thingy in it's corner. This is the virus breeder, and when you first see it it doesn't do much.
HOWEVER!
Dotted around the cyberworld are several groups of enemies that only shw up on one exact square, and when defeated are downloaded into the Virus Breeder. There you can feed them BugFrags. Feed them enough and they'll get more powerful, giving you chips to call them in battle, like MegaChips only these are normal ones, and therefore with no limit to how many you can have in your folder. The chips you receive are shown at the bottom of the page.

Basic Virus Locations:

Family	Picture	Location	Tips
Mettaur		ACDC 1, on the other side of the purple door. You need the WWW-ID from  job 17 to do this.	They're only Mettaurs. ^^
Bunny	-	Complete Job 20	-
Spikey		Go to Hades Island and jack into the right Gargoyle. Go up.	Not hard. Their only attack shoots forwards so they're easy to dodge.
Swordy		Go to Undernet 1 and follow the blue path. Turn left at the end and stay on the blue path. Swordys are at the very end.	Again, not hard, since they only use sword attacks. Kill them before they can use AreaGrab and you'll have no troubles.
Jelly		When heading to the Undernet entrance, turn left and go past the purple barrier instead of going to the warp. They're at the end.	Now it gets tricky. Since they're only vulnerable when they're lower down and there are no obstacles in your way, their attacks will hit you every time. Bring a RockCube though and you'll have to trouble. Just pop out from behind it and shoot them when they go low. Otherwise, use powerful Megachips and long-range attacks.
Mushy		From the Cyberline in SciLab 2, go up the stairs and go left twice, they're at the farthes point.	Bah to 'em. Take a good number of fire chips and hammer away. Their attacks only confuse you and do little real damage, and this doesn't affect your attacks, only your movement. FlamMan is great here.
KillerEye		Go into the Principle's computer, past the green Navi, and then walk along the big screen until you find them.	Too easy. The middle-middle and middle-left squares are completely safe. All you have to do is shoot them when they aren't looking in the direction you want to move.
Momogra		Go to where you fought BeastMan in the Zoo comps. They're at the back.	This one is considerably harder than the others. It's basically a game of cat and mouse. Sit on the first row of your area, and when one appears behind you quickly dodge around him and smack him. It's real trial and error unfortunately. The Meteor attacks work very well though.
Scuttlst		Head left from the entrance to the Secret Area.	Hard hard hard! All three of them have Auras that need to take 100 damage before they break, and their attacks are a bitch to avoid. The blue one throws blocks of ice along the row it's on, the red one is like a FlamMan chip, expcet the flames follow you across the rows, and the yellow one shoots you with bolts of lightening! Make sure you have a LOT of high-power MegaChips. ProtoMan, PlantMan and Kingman work well. the Meteor attacks will again come in handy. It's hard to make an effectie strategy against these guys. If you're lucky you may be able to chain PlantMan chips and Meteors.
Scuttlst 2		(You must have all the other viruses to do this) In secret 3, go down the small path to your right, and keep heading right. They're at the dead end there.	The purple one fires a huge beam across the whole row every second or so, and the green one has the 'creeping vine' attack that PlantMan has. Both also have an Aura that can sustain 100 damage before collapsing. Just hit them with everything you have. If you got this far you should have learned to dodge attacks like this pretty well

The looting and pillaging capturing phase is complete!

Feed your Viruses!

You can feed any one virus family up to one hundred BugFrags. Talk to the green Navi and it'll let you redistribute the food. You can take away or add 5 BugFrags at a time to a Viruses' bowl using the left and right direction buttons, but the number in all three Viruses' bowls can never exceed one hundred. The more food, the more power that Virus has. A good combination is:

The sustenance phase is complete!

Once you've fed a virus family one hundred BugFrags, talk to the green floating Navi beside them and it'll tell you where their boss is. Now you gotta go find him.

Viruses Bosses

Boss	Picture	Location	Tips
MettaurΩ		ACDC school blackboard (your class).	Basically the same as every other Mettaur you've faced, with the exception that their wave attack now cracks panels, so be careful where you dodge to.
BunnyΩ		Jack into the hospital bed where Yai was staying (last door, 2nd floor)	Just your standard Bunny, only a little faster and more powerful. No surprises here.
SpikyΩ		Hear the exit to Zoo 3, at a figure-of-eight walkway, go to the upper-right and they're at the last square of the dead-end.	Fast and powerful. If you brought some CrosShlds, this is the place to use them. Activate them when the fireballs comes flying towards you and chances are it'll get bounced right back at them. Otherwise use wide-effect chips like TrplBomb or homing ones. You're bound to hit one of them.
SwordyΩ		The Zoo warning bell. It's behind and all the way to the left of the Panda cage, and not visible. Just go right as far as you can and jack in.	These guys will AreaGrab you to hell if you don't hurry up. They have Sword, LongSwrd and WideSwrd attacks, so kill at least two before all but the last row is taken from you. High-power chips is the way to go here.
JellyΩ		Jack into the panel to the left of the Yoka outdoor bath.	Not as hard as it first seems, because if the first one hits you, you'll still be staggering (and thus invincible) when the next two pass over. Use powerful chips when they're hovering low to the ground. That's it really.
MushyΩ		On the Hospital 3rd floor, jack into the panel of the emergency stairs.	Beware, this is hard. Unlike before, the fumes do real damage. Use plenty of Ratton, Roll, PlantMan type chips to home in on them when you're confused (and believe me, you'll become confused). Just hope you kill them before they kill you.
KillrEyeΩ		Walk into but not past the archway going into the SciLab Virus Lab and jack in to the right-hand side. If you're in the right place you'll jack in.	Now begins an interesting game of dodge-the-rays. Move down to the bottom row a soon as you start the battle to avoid the top two beams, and hammer the bottom Eye with attacks. When the Eyes change direction (they'll blink when they do), move u to the middle of top row to avoid the bottom one. Keep alternating between this to avoid any damage.
MomograΩ		Where you fought BubbleMan.	Yup. Same as the last time. Just wait, then dodge. Remember that the back row is a totally safe area if you need to think about what to do next.
ScuttlstΩ		After getting of the boat at the WWW base, go all the way up into a small pathway and jack in when you can't move anymore (you can't see yourself)	Surprisingly this is slightly easier than the previous one. Since both of them only shoot beams across a row, there's always one row that is safe. Each of them has a 200-damage strong Aura though, so make sure you packed plenty of chips.

Name	Picture	Letter	Inflicts	Element	Description
Mettaur		T	?	-	Mettaur wave runs along one row at varying speed
Bunny		R	?	Electric	ZapRing of varying power travels across row.
Spikey		E	?	Fire	Fireball flies forwards across row
Swordy		W	?	-	Swordy slashes in front of it. Effect varies
Jelly		Y	?	-	Wave travels across screen.
Mushy		H	?	Wood	Spice of varying power travels around all squares surrounding it.
Momogra		G	?	-	Mole appears and hits enemy one space in front of it
KillrEye		K	?	Electric	Beam flies in direction laser was pointing when button pressed
Scuttlst		A	?	All	Varies. Fire, Electric, Water, Wood and normal attacks all possible

Congratulations.

Another section done. You still can't have more than 100 BugFrags assigned to them all, so you may have to make some alterations depending on how lucky you are when it comes to pressing the button at the right time.