Tim

Tim is a Caster skeleton found in the Underground. He can be recognized by his Wizard Hat. Just like any other caster, he will randomly teleport himself to a visible part of the screen after shooting three projectiles. Tim was added as a rare spawn during the 1.0.3 update.

Finding Tim
Tim can be found anywhere in the Underground and Caverns layers. Its spawn rate is low and completely random, but it seems to increase with Depth.

Drops

 * Wizard Hat

Trivia

 * His name is a reference to Tim the Enchanter from Monty Python and the Holy Grail, this was confirmed by Blue on the Terraria IRC.