Take 'em by surprise

"Breaking news!" I tell my sister. "I killed a spider in the bathroom by throwing water around it so that it lost its footing and got swept into the sink & down the drain! That way I didn't have to clean up spider guts by killing it another way!"

Rebecca replies, "But it might survive and crawl out, so I always kill them."

At least I made sure so much water followed it down the drain that it couldn't possibly have survived.