Make trappers and lurkers above mindless, so they’re not trivial to find and avoid with telepathy.

Trappers’ and lurkers’ above digestion happens much more quickly than purple worms, on a shorter timer. As it stands, most digestion attacks aren’t very threatening as an instadeath because the player almost always has time to kill the digester.

For that matter, all digestion attacks should probably be accelerated somewhat, even those of purple worms.

Drop bears: possibly t-class monsters (or z-class, if the SLASH’EM zouthern animals monster class is used) that hide on the ceiling, generating next to or near trees. They are unimpressive in combat, except for the nasty amount of damage they deal with their initial dropping attack. Can only go back to hiding when next to a tree.

A t-class monster that generates on a wall space and pretends to be part of the wall, then attacks/eats you when you step next to it.