Hello.
Each model is made on an Epic skeleton.
Alien 1 and Alien 2 also have animation sets.
ONLY DEFAULT UNITY SHADER + In the model Alien 3 it is desirable to use a shader with a two-sided display of polygons.
NO HDRP/URP
Before buying, read the technical details and watch the pages and videos for full information.
Alien 1
https://assetstore.unity.com/packages/3d/characters/creatures/alien-1-249728
Alien 2
https://assetstore.unity.com/packages/3d/characters/creatures/alien2-249732
Alien 3
https://assetstore.unity.com/packages/3d/characters/humanoids/sci-fi/alien-3-259621