VIDEO: Clay Matthews steals Kaepernick's celebration after sack

Sunday was not a good day for Colin Kaepernick, thanks in part to Green Bay Packers linebacker Clay Matthews.

First Matthews reminded the San Francisco 49ers quarterback - who finished the game with just 160 yards passing and an interception - that he wasn't Russell Wilson.

Then, after Matthews sacked Kaepernick in the third quarter, he stole the quarterback's signature celebratory flex and bicep-kiss:

Clay is cold-blooded.