Johnny Manziel
Manziel had arguably the greatest college season ever in 2013. He changed the face of the Aggies’ program as he won the Heisman, Davey O’Brien, and Manning Awards. No freshman had ever achieved this before but it appeared Manziel was special. There were concerns about his maturity and focus but the Browns made him a first-round pick in 2014 anyway.

Manziel burnt them because he partied crazily. He had substance abuse problems and failed to deliver on the field. In the end, he went down as one of the biggest busts ever and set Cleveland back for almost a decade. He had an amazing time in college but he proved it was too good to be true (via Sporting News).