What happens when you beat the Eye of Cthulhu?

What happens when you beat the Eye of Cthulhu?

When the Eye of Cthulhu falls below 50% health (1,400) in normal mode, or 65% health in Expert mode ( 2,366 ), it transforms into its second form (shedding its iris into a mouth), which rams the player more aggressively 3 times, then hangs in the air for a period.

What gear should I have to fight the eye of Cthulhu?

As people are saying, you don't have any specific requirements for beating the Eye of Cthulhu or any of the pre-Hardmode Bosses for that matter, but gear makes it much easier on you. I would recommend having silver armor, sword, and bow but it is not needed.