The Ultimate Showdown

"It's time for some bustin' and smashin'! The Ultimate Showdown has started!"

The Ultimate Showdown is both a pre-Hardmode and a Hardmode event where nearly every enemy in vanilla Terraria swarm the world's original spawn point. It cannot occur randomly and can only occur when the player uses a Demonic Lemon.

On single-player, the player must kill 200 enemies before the event is completed for both the pre-Hardmode and Hardmode variants of the event. This number increases by 200 with every additional player.

Summoning
The Ultimate Showdown can only be summoned manually using a Demonic Lemon.