I broke the gear retraction system on a Seminole by trying to bring the gear up with a snake (that I didn't know was there) curled around the left main gear.
Years before Bambi was Bambi, I put a large crow through the radar dome of 709 coming out of Charlotte. Also I jammed a pretty big bird into the horizontal stab of a -200 on the way in to HPN. Damn near tore the yoke out of my hands.
Only other notable hitchhikers were about a billion mosquitoes that were in a -200 that had been sitting with its door open on the ramp in Greenville Mississippi for a day or so after coming out of the paint shop there. Flew down from DAY at about 11 at night to drop off a different plane to get painted (and almost tore the wing off on a unmarked concrete pole in the middle of the ramp) and then wandered over to our bug infested ride home. Also, they'd never dumped the lav when the plane was flown down a week earlier and the inside was pretty terrible. Remember just wandering into the pool of darkness past the right wing and going to the bathroom out there instead of daring to open the lav door.
Got bit about a hundred times while I waited for the APU to get going so I could turn on the packs and get the gasper vents open to blow enough air around to push the bugs out of the cockpit. There is a slightly better than non zero percent chance that
@DeltaAlphaNovember was the FO on that but I can't remember... I think the guy was getting furloughed in a few weeks and was an army rotor guy, but it was a long time ago.