Boils are spawned by Gurdy, the green alternate Chub, the pink alternate Widow and also found in rooms as enemies. They start off as a small red sphere and slowly grow to full size. When full size, they will spurt out blood that can harm you. They'll decrease in size when hit but will regenerate to their full size until fully destroyed.
Boils are nearly harmless on their own, as you can simply kill them from a distance and do not deal damage on contact. With other enemies, however, they are far more dangerous: If entering a room with a large crowd of enemies and several boils providing covering fire, taking out enough of the boils to give yourself breathing room should be a big priority. Since they do not harm you on touch, you can use the virus to kill them before they grow too big.
Champion VarietiesEditDouble HP.
Guts have different projectiles, they shoot with explosive shots at close range (same projectiles as Sloth) and can cause 1 heart of damage.
They can easily be a nuisance if there are other enemies backing them. However, they are rather easy to manipulate into destroying rocks or finding secret rooms without using a bomb.
Sacks don't shoot projectiles, however in close proximity they can spawn small spiders. They will not spawn spiders unless at full health, meaning that shooting them will render them harmless until regenerated.
They are often found with small spiders in a room and can be an annoyance if they are not disposed quickly as they can spawn other small spiders on you.
Tips: If you have the Charm Of The Vampire item, you can use Sacks to spawn spiders which can be killed to heal yourself.
These enemies resemble webbed sacks (and thus look similar to the item Daddy Longlegs).
The walking variants attack like their normal variants, however they can walk. They are most commonly found in Necropolis. These enemies do not regenerate HP like their counterparts and can immediately attack without having to swell to their maximum size, however damaging these variants do not reduce the swelling of them.