Maggots simply crawl around the room blindly in cardinal directions, not targeting Isaac. Because they don't follow Isaac and move very slowly, it is easy to avoid them. Maggots are thus only dangerous in great numbers and enclosed areas, where it can be difficult shooting at them safely without running into them.
Chargers are a more advanced form of Maggot, and they're encountered more often as well, present in The Caves, The Catacombs and The Depths. They possess a smiling face of sorts, and look quite harmless as they slowly crawl along without attempting to follow Isaac. If a Charger lines up with Isaac vertically or horizontally, they will immediately and quickly charge in a straight line towards him. Because they're always encountered in groups of at least four, avoiding them quickly becomes a problem.
Chargers do not seem to notice Isaac unless he is moving. If Isaac stands still and a Charger lines up with him, they will continue crawling without attacking him.
Chargers can be spawned by Chub, Sloth, Pestilence and Fistula (only upon destruction of smallest parts). They are also spawned upon the destruction of the Green Champion version of The Hollow's body segments.
Spities are much fatter than other maggot forms, possess a face like Chargers, and have the same health as them. Instead of charging the player in their line of sight, however, they spit shots ahead of them while slowly crawling along. They have a good range but a slow firing rate, and because they ignore Isaac, their shots are easy to avoid.
- Sometimes, Chargers get stuck in gaps until Isaac comes too close and lets them charge.
- If the player avoids moving once entering a new room, the Chargers may not perform their charge even if they get a clear line-of-sight.
- Spities can sometimes shoot at opposite site than the on they're facing (i.e. They look away from Isaac but still shoot at him).
- Maggots tend to get stuck in open doors.