Someone broke into one of Penn's equipment sheds during the USATF Club Nationals last weekend and stole Mattis' discus. Penn people claim the shed was locked, the discus was in the shed before the meet, and it was the only item unaccounted for once the meet was over.
This discus was the one that Mattis used to set the American Collegiate Record earlier this year, as well as qualify for the Olympic Games.
That's a low blow for someone to go in and steal the discus.
http://hepstrack.com/blog/2016/06/30/missing-one-historic-discus/