BW mob spawns: wurms in Skellie house
 

It appears to be possible for Wurms to spawn in places of the 2 walkers that path THRU the skellie house at approximate loc(-1000, 2000). I camped this house for many hours on live, the walkers that path thru the house were never wurms or sarnaks; Only gorrillas and SKellies. again this is just for ones that path through the house i can't speak for paths that do not pass through the rooms.

Take that for what its worth. just my 2 cents, as I recall things; but wurms are far to big to path through the house and if you see this, it will look quite odd.