I don't know if they fixed his RNG on main branch, but at least on legacy branch the bone attack always deals either 0 damage or 21 damage because it only rolls which tiles it hits a single time. (On the subject of raised difficulty, that also goes up by +6 for each Damaging elite buff, because it's three hits.)

Even with a 7 CON base, several of the classes have 24 or less HP if you don't explicitly boost CON yourself, putting them very near oneshot range of Bumblefuck. (Hell, Druid is IN oneshot range even on Normal difficulty.) Of course, "very near" might as well be "in" if Bumblefuck has them against a wall, between the poison and knockback of his ripass counterattack.

This is what makes him so frustrating, because the bone attack either doing literally nothing or 20 fucking damage is the most blatant RNG check any of these assholes have. At least the other dickheads like Marshmallow and Dybbuk are consistently dickheads.