Whips & more mod/Oreo Sniper

The Oreo Sniper is a Post-Moon Lord enemy that spawns after Corite Knight has been defeated.

It follows the player, and shoots cream blasts at the player.

The cream blasts get heavily buffed in Expert Mode.

It drops Oreo Cookie Ore and Oreo Cream Ore which is a material for endgame items.

Spawn
It spawns at night, though pretty rarely.

Having a Blood Moon active, a Water Candle nearby, and using a Zerg Potion can dramatically increase the spawn rate, allowing you to get the ores much quicker.