I had my grandma take care of my bichir once.
I just told her to come over once a day and check the tank temperature, and make sure the filter wasn't clogged. I gave my fish feeders because it was easier than explaining how to feed her.
When I came back, my grandma showed me the bite marks all over her hand from when she tried to take the bottle my fish hid in out because a feeder was hiding in there...which of course my bichir guarded with her life. To quote her "Your fish is the meanest little monster I've ever seen, I went to take the little fish out and WHAM it's on my hand and rolling around!"
To be honest, it was a pretty nasty little mark on her hand, I can only imagine how horrifying it was to have a 6" "snakeyfish" deathrolling your thumb.