Seriously. Bugs are intriguing to me. A set code of equations and still...crazy legs. I shall do some research.
Similar bug in BF3 was hilarious and it looked like guy was running akwardly because he had crap in his pants.
Well, bugs often leave eggs incubating in some of the deeper reaches of game code. The eggs can be very hard to detect, so even when the bugs are exterminated, there's a chance their offspring will hatch and cause havoc once again. Conditions become favorable for hatching typically as a result of a major game update. The eggs sense such a change in the environment and break free into their natural habitat.