If an anaconda is put into a closed space with a layer of hoppers as the floor, and a layer of dirt blocks under it, several issues will occur:

1. Only the head is correctly placed on the hoppers, and the tail gets stucked through the hoppers and is placed on the dirt layer. This always occurs.
2. The tail often partly gets outside the space through the wall while the anaconda randomly moves in the box.
3. Rarely, the anaconda can attack mobs outside the box through solid blocks.
4. Rarely, the whole anaconda may get out of the box through solid blocks.

Minecraft version: 1.18.2
Forge version: 40.1.68
AM version: 1.18.6

To reproduce:

1. Make a closed box with opaque solid blocks (e.g. dirt blocks).
2. Place a layer of hopper on the bottom inside the box.
3. Spawn an anaconda inside.

• The picture below uses glass as its wall for showing objects inside. Opaque wall (planks) was also tested and the result was the same.