Depends what you mean by deadly. I always thought my deadliest spell was when I walked three batsmen, breaking two toes and a nose. Okay, they weren't wickets, but they couldn't continue playing.
I'm always curious when one guy bowls so well and others don't appear to. I know when I took 8-12 I was the only one who swung the ball all day on a flat deck. I took 8-22 in one league game at Windsor because the sun was setting behind my left arm over and the last 4 bats couldn't see it lol
I've often had games where I bowl 10 or 12 overs at an economy rate of around 1, but only get one wicket as either the batsmen simply can't get bat on the ball, or it's bouncing over the stumps off a good length. Generally, the other end then gets 5 wickets, frustratingly. All about bowling in pairs!