Spawns random enemies in front of every door and closes the doors.
Enemies also spawn in front of connected Secret Rooms and Super Secret Rooms if there are any next to the current room.
Spawns an item pedestal that rerolls between 9 different items 30 times per second. The item selection is from the current room's item pool. (ex. if the item spawned in a devil room, you could get Brimstone as one of the 9 items)
Spawns many colored beams of light around the room that deal damage to enemies. These beams of light scale with Isaac's damage, and get exponentially stronger the more damage Isaac has.
Flips all sprites to the side, gives Isaac random tear effects for the rest of the room, and permanently increases and decreases one of Isaac's stats, similarly to Dataminer.
Spawns many shopkeepers around the room. These have a chance to be special/error shopkeepers.
Spawns a giga-bomb pickup that gives Isaac a bomb and converts his next bomb into a giga-bomb that deals 300 blast damage, spawns many rock projectiles that deal 15 damage, and creates 13 holes in a diamond shape around the blast zone that deal 99 damage to enemies that were in their areas. These holes cannot spawn if they would close Isaac's path around the room.
This bomb has a chance to be live when it spawns.
9 Volt: Fully recharges Everything Jar upon pickup. It also slowly recharges Everything Jar's first charge while Isaac is in an uncleared room.
Car Battery: Instead of doubling its effect, Everything Jar will spawn a poop alongside its normal drop.