From the Super Mario Wiki
Skeet is a resident of Flipside from Super Paper Mario. He is a young man currently studying on how to become an architect. He roams around Flipside's Third Floor every day and never seems to get any work done. He stares at the tower every day, and Tippi thinks he should really start building his own life before he starts to build any buildings. He is the one that finds Princess Peach lying on the ground after she is teleported by Dimentio from The Void. He alerts Merlon of this and takes him to Peach along with Mario.
Skeet’s counterpart from Flopside is called Pete.