Chaos Core

Very Rare Spawn

A zombie horse jockey may only spawn while raining or thundering. The chance is very, very low to get even a regular sized zombie horse. For it to be a baby variant, you'd need twice that luck.

Adult Zombie Jockey

The chicken despawns after its rider dies, so you can't keep the enlarged chicken. Sticking with vanilla.

Total Blood Moon Chaos

This is in version 1.0.2 where the blood moon was beefed drastically. I ran around for about 4 minutes without slaying. This is what I was facing accumulatively outdoors.

Creeper Riding Phantom

Riding creepers' blasts are reduced.

Blood Moon Horde

Blood Moon Event (New Moon Phase)

Armored Z-Pig mounted on a Zoglin