Overworld Ultra Beasts

Modification for Minecraft allows Ultra Beasts to spawn in the regular world. This solution was adopted because Ultra Space is currently under development for version 1.16.

Ultra Beasts appear using the legendary Pokémon timer mechanic. However, when they appear, there won't be a chat announcement - this is a feature of Pixelmon itself that can't be changed when using the legendary Pokémon system.

Spawning Biomes

Blacephalon: flower biomes
Buzzwole: jungles
Celesteela: savannas
Guzzlord: mesa biomes
Nihilego: river biome
Poipole: swamps
Stakataka: mountain biomes
Xurkitree: birch forests

Biomes specified in quotes also work with biomes from other mods such as Oh The Biomes You'll Go and Biomes 'o' Plenty.