The warning label on the sides of disposable butane lighters that say "Do not keep lit for over 30 seconds" are there for a good reason. If you do, in fact, keep a lighter lit for more than 30 seconds, the flame will suck back into the lighter, making a "Zoop" sound. This will cause the lighter, with all of the remaining fuel left in it to violently explode, and can result in a serious injury. I do not encourage anybody to try this.
"Hey, look out dude! The lighters gonna Zoop on you!"