Present Revealed

I received a phone call at work yesterday from my mom asking me if I had left red sock yarn out at home. I pinched my eyebrows together and replied,"no, why?" Her reply, "Well, there was a skein on the second floor landing and one in the cellar." Mom didn't find the stash drawer open, it was a puzzle. Then it hit me. Andrew. Only Andrew could open two plastic bags to steal two hanks of sock yarn out of my bedroom on the second floor, deposit one on the landing and carry the other downstairs, through the cat door and into his room in the cellar. "Uh, Merry Christmas mom. Those were supposed to go in your stocking. I'll have a chat with Andrew when I get home."
"What sock yarn?"