Mock ye not the humble BUB. Doing practice bombing with BUBs on a friendly snorkelling O-boat off Singapore, boat suddenly surfaced and became less friendly. Turned out one BUB had hit the snorkel mast and all the smoke had been sucked into the boat.
Came across the boat's captain 35 years later, and his first comment was " You're the B----- who sent all that smoke down my chimney". Apparently it does not smell nice.