Cool Uncle Share definition Flag Mark Rober. A uncle who worked at NASA and now makes genius videos on youtube Frank: Hey, that’s a cool uncle! Jerry: Yea, he’s Mark Rober! Frank: Cooooooooooooooool! Cool Uncle by Dinglederper May 28, 2020 0 0 Get merch Get the Cool Uncle mug. Buy Now — $32.95 See more merch