Worms are creeping or burrowing invertebrate organisms with long, slender, soft bodies and no limbs. Worm might refer to:
- Larry Jr. - A boss that appears in The Binding of Isaac and its remakes.
- The Hollow - The posthumous version of Larry Jr. that spawns in the Catacombs.
- Pin - The younger version of Scolex and first appeared in Wrath of the Lamb.
- Scolex - A worm-type boss that can only be damaged from behind and fought in The Womb.
- The Frail - The posthumous version of Pin and first added to The Binding of Isaac: Afterbirth.
- Round Worm - An enemy that burrows and fires blood shots.
- Nightcrawler - An enemy that shoot four shots around it in a swirling pattern.
- Roundy - A worm that forms damaging rock waves and spits IPECAC shots.
- Ulcer - A special kind of worm that spawns Dart Flies and rarely shoot blood shots.
- Flat Worm - A trinket that increases knockback and give Isaac oblong tears.
- Hook Worm - A trinket that increases range makes Isaac's tears moves in a right angle based pattern.
- Lazy Worm - A trinket added in The Binding of Isaac: Afterbirth and increases range and tear height but decreases shot speed.
- Pulse Worm - A trinket that changes the hitboxes of tears and makes them pulse in size.
- Rainbow Worm - A trinket added in The Binding of Isaac: Afterbirth and gives Isaac a temporary, random worm trinket effect every three seconds.
- Ring Worm - A trinket that causes Isaac's tears to spiral at fast speeds and slightly increases effective range.
- Tape Worm - A trinket that increases range and tear height.
- Whip Worm - A trinket that increases shot speed.
- Wiggle Worm - A passive collectible that makes Isaac's tears move in a wavy fashion.
- Wiggle Worm (Rebirth) - The trinket version of Wiggle Worm.