Penn & Teller material varies from light-hearted gags such as graphic tricks and clever pranks to tackling issues through political satire and by exposing frauds. Many of their effects in their past relied heavily on shock appeal and fantasy violence, although presented in a humorous manner. Some of their more daring tricks included Teller hanging upside-down over a bed of spikes in a straitjacket, Teller submerged in a glass tank of water, and Teller being run over by an 18-wheel tractor-trailer. Penn & Teller will often present tricks that they initially appear to have botched, in the "trick gone wrong" vein.