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. As suggested by their names, they can charge toward Isaac when lining up.
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.
Eternal Charger leaves green creep while moving. After certain time, it will change into an Eternal Sack (the Sack will not shoot Spiders). And eventually, it will become a stronger Eternal Fat Fly that shoots 3 projectiles.
The whole metamorphoses progress is very similar to how Maggots do.
- 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.
- Sometimes, Chargers get stuck in gaps until Isaac comes too close and lets them charge.