I have seen receptacles melee me in the log without terroanima being used before, however it is very rare and probably a bug, and I've never seen it happen more than once at a time, let alone a bunch of times in a row like in the OP.

Originally Posted by
LinktheDeme
Terroranima doesnt matter what you target you could be targeting yourself and it will still work.
I don't know what the hell you're talking about, but terroanima only works on one target, which is the one you use it on. Mobs under the effect of terroanima can still melee you if you're in range, so this is what probably happened to the OP, since a receptacle obviously can't run out of range.