Caster AI

Creatures with Caster AI follow one distinct pattern. Caster AI creatures do not run or jump; instead they teleport to onscreen locations and shoot three missiles that pass through blocks. These missiles can be destroyed by being hit. When hit, casters become stunned and do not teleport or fire projectiles. However, if they stop taking damage, they immediately end their current cycle and teleport to another location. This makes very slow weapons like the Fiery Greatsword somewhat ineffective against casters. Stunned Casters suffer knock back on damage, take damage from lava and can suffocate (rare due to their teleportation).

As of patch 1.0.5, Caster AI was modified to have a larger delay between each of the three shots, making caster mobs much less dangerous and giving the player more time to reach them before they teleport again.