VIDEO: Kirk Cousins takes a knee instead of stopping clock

What were you thinking, Kirk?

With six seconds left in the first half of Saturday's game against the Philadelphia Eagles, and the clock about to run after a timeout, Washington Redskins quarterback Kirk Cousins made a colossal mistake.

Cousins, inexplicably, took a knee instead of spiking the ball to stop the clock.

Cousins did realize his mistake, trying to quickly spike the ball after taking the knee, but the damage was already done.

Cousins' mistake cost the Redskins at least three points, with the clock winding down to halftime after the knee.

Redskins head coach Jay Gruden was equally bewildered with his quarterback's decision.

"I don't know why Kirk took a knee, I'll find out at halftime," Gruden said during an on-field interview.