Smoke tubes are used when truck and tractor pulls are indoors. A big tube is pulled behind the tractor which sucks away the filthy diesel exhaust.
There’s a lot of exhaust to suck away.
Of course, the crowd goes wild when the pipe slips out of the hole and the black jizz covers them all.
And a video of the setup. But I saved the best part for the end: the blower which sucks up the exhaust and blows it into the sky! That way everybody inside gets clean air while everybody around the stadium gets the soot.