I have a idea. A trap for every terraria boss with their own little things.
Here's my ideas, for this idea:
King Slime - Spews slime around the area, slowing down enemies and giving them the Slimed! debuff, which makes them look blue and sticky, and deals damage over time.
Eye of Cthulhu - Releases a wave of baby demon eyes, blinding enemies
Eater of Worlds - Devours an effected enemy, pulling them down slowly and dealing damage until they are sucked into the earth and killed.
Brain of Cthulhu - Releases a swarm of parasites, infecting enemies and causing them to attack each other.
Queen Bee - A hive of bees that attracts enemies to it with the sweet smell of honey. When the enemies destroy the hive bees will swarm them before going back to the hive and rebuilding it.
Skeletron -Curses an enemy, transforming them into a skeletal version that attacks their allies.
Wall of Flesh - Releases the souls of nearby enemies, causing them to be slowed and deal less damage until they return
I'll do the Hardmode bosses later.