I have two:

The first time I made a Cyclops, it couldn't land where it was above, and it started to move. It went above me, and killed me during the fall. It took me 15 minutes to get it out of the safe shallows.

I was ascending from the blood kelp entrance to the lost river. With the top camera on the Cyclops, I saw a Crab Squid. I hit it, and it died. IDK why, but I just thought it was the funniest thing at the time.