Fabric softener is a product that Captain Underpants thinks can bring back his powers after he gets sprayed with starch. He acts this way due to the placebo effect, after George and Harold made their new comic "The Wrath of the Wicked Wedgie Woman". After Robo-George and The Harold 2000 sprayed him with spray starch, Captain Underpants falls and gets hung from a pole by Robo-George.
George and Harold then made a new comic called "The Origin of Captain Underpants " which says that Captain Underpants is immune to starch because he swallowed the magic amulet that made his home planet, Underpantyworld, immune to it. Captain Underpants has to say "I summon the power of Underpantyworld!" and he would overcome the evils of starch.