Yoo Jae Suk showed naughty hand action on Gary for victory.

In SBS "Running Man" aired Sunday, a Christmas special was shown.

On this day, Yoo Jae Suk and Gary were on red team together, and they all had to move from one end of the mattress in a pool to the other end. They had to help each other not fall.

But when Gary was about to fall after losing balance, Yoo Jae Suk grabbed his butt to save him, arousing laughter.

Photo Credit: SBS