Seep on T-layer on wall: It's
established that you can build T-Layer things under monsters.
I do think it's an exceptional case, though, and editor should not allow such placement by default because 9999 times out of 10000 you'd rather have the monsters around the bombs, kegs and mirrors. I think we should make seep have the same placement rules as other monsters in this specific case.
Gentryii head on walls: I think this comes from the fact you place their chains on a wall. But since we don't allow any other monster to be placed on top of a wall I'd say - change this so that head has to be one the floor. This would be consistent with the fact you can't build walls under monsters at all (though you can turn into monster on a wall).
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