namreeb
Serpentshrine Cavern
In the middle of the pool from which Lurker is summoned, mobs need to be able to climb out of the water seamlessly onto the platform and back again. No coords needed since you cant miss that part of SSC.
I haven't added any water support yet. I need to do more research into it, but this helps as a good example of an edge case. I think usually creatures can either be in the water, or on land, but not both. Another edge case are the partially submerged pirate ships off the coast of Wetlands.
When underwater, mobs ignore obstacles completely. They will happily swim right through the side of a ship, or a wall.
Ref: https://streamable.com/21tcje