In the third book of the series, Captain Underpants and the Invasion of The Incredibly Naughty Cafeteria Ladies from Outer Space (And the Subsequent Assault of the Equally Evil Lunchroom Zombie Nerds), The Dandelion of Doom is an ordinary dandelion turned evil on accident by the growth juice poured out the window by George & Harold. We first see the dandelion when Captain Underpants uses his cape as a parachute, since attempting to swing onto the ground using toilet paper hadn't gone as planned. As the three are parachuting down, they unfortunately land near the overgrown & evil dandelion, with the captain getting himself caught between the jaws of it. Thankfully, the boys give the captain some super power juice in order to defeat the dandelion, which they eventually do. The Dandelion of Doom only appears in the third book, as it's defeated in the same book aswell.