Papa Cosmo-Cosma is Cosmo and Schnozmo's father, the spouse of Mama Cosma, Wanda Fairywinkle-Cosma's father-in-law, and the paternal grandfather of Poof. He was turned into a fly by Cosmo when he was a baby and got his first wand.
There are roughly one-sh*t billion tropes so PLEASE look through them before adding one. Otherwise add what you like. ADDITION: PLEASE read through the trope description provided before submitting something. It's not a huge deal but too often people submit characters that don't fit just because they misinterpreted the title...