[Vanilla Bug] Polymorph-Trap Edge Case

[clockfort]

There is no message for when a monster suddenly seems to disappear, when they step onto a polymorph trap with objects on it, and they polymorph into a [snake|spider|similar] that immediately magically hides underneath these objects.

It would be more sane if the game said "The fox disappears from sight!"

[eatnumber1]

You don't normally get a message when a snake or spider hides under something. You want one to be added which is only displayed if the monster has just been polymorphed?

[clockfort]

I'm not sure what the proper thing to do would be. It's just weird for a fox to walk up to a pile of items, disappear from the map without a message, and then have a snake suddenly attack you when you get close to the pile.