Yes, you should try every kind of food in your waffle iron. This one’s the simplest, though: Just stick some premade puff pastry in the waffle iron and see what happens.
Food & Wine calls the result a “croffle”: croissant + waffle. The dough does take on that crispiness on the outside and flakiness on the inside, fluffing up more than you might expect. You can treat it like a waffle, too, pouring on maple syrup on top or making your own pastry dough and folding in chocolate chips.
Either way, come on, go buy a waffle maker already.
How to Make Croissant Waffle [Food & Wine]