Meltdown by Jimmy Strange is a complete impromptu effect using an everyday lighter!
Get a spectator to check out the lighter; the magician then takes it back and sparks a flame to heat up his hand then seemingly using the heat, stretches the actual plastic with his fingers. It can then be handed out to show that it is still fully working.
Meltdown truly stretches the imagination. Comes with one fully working lighter and one fully working gimmick lighter. Also has an added bonus effect with a card revelation on the stretched label.