What does beating on a goatmen drum do? [duplicate]
I have seen the goatmen grow larger when beating on the drum. Not just the drummer, but all Kazra within a certain distance grow larger. Shortly after the drumming stops (either they hit whatever limit they're looking for, or you destroy the drum), the goatmen will shrink back down to normal size.
The only ability I know of that makes monsters grow is Avenger, where champions grow larger and hit harder when you kill their friends. I suspect the goatmen's larger size is to convey the same information; they hit harder.