has anyone’s mermaids successfully drowned a sim?

I was looking forward to having an evil mermaid too.. Darn. It does seem impossible to kill sims when you want them too. I think it took me 4 days to kill an elder sim and that was making her whoohoo in a rocket to exhaust her and still she lingered. I swear the easiest way to kill a sim is make them silly, a comedian, and then have a toddler or pet to play with and they will die of being hysterical before you can catch them sometimes... I've had to save at least 5 sims from dying from that so it's my new "you must die" go because it's much faster than locking them in a room for days. Although maybe touching the lava bombs would be faster now?