it's trying to kill a venomous spider in order to lay an egg inside of it, which will eat the spider as it matures.
the result presented here makes the behaviour seem like such wantonly pointless violence. ok, ok - maybe it's going after a competitor. but, surely there are less dangerous ways to lay some eggs...
it's stuff like this that makes you realize there's no way this shit was designed. this defies all reason. and there's thousands of similar examples.
https://www.youtube.com/watch?v=TQNgxJdqzm4