When Tippy returns to the present, he finds the planet destroyed as a result of his meddling. Giant-Zombie-Nerd Harold apparently steps on him, leaving a red squishy stain and supposedly preventing him from restoring the original timeline. Luckily, Poopypants really just faked his death so he survived
It is revealed that Tippy faked his death, and the red stain is merely from a giant ketchup pack. Tippy returns to the past and restores the timeline, causing this version of George and Harold to cease to exist.