That's DeMarcus Cousins on the top left. He's supposed to be playing defense, but he is behind Marreese Speights from the very beginning of the inbound play. Speights cuts right to the rim for an easy lob dunk and Cousins doesn't move an inch. Doesn't stand up straight until the play is over. Cousins and Speights even appear to exchange words before the play, like: "Hey you should stand in front of me. That's how defense works. I'm gonna cut to the basket." "Nah, see ya."
Cousins has done this before, too! Watch him on this Rudy Gay offensive possession from a few weeks ago (via r/NBA):
Exact same thing, hands glued to knees and all. Boogie just doesn't feel like it sometimes. We've all been there.