Lyle is a Muppet sock who, with his mate Argyle McSock, works in the stockroom of the shop on Big Bag. When they're not hanging out in the store's sock bin, they can be found in a laundry hamper or just chatting with the other main characters.

Lyle loves to tell knock-knock jokes to Argyle, replacing "knock-knock" with "sock-sock!" He is suggested to be from New York, due to his Brooklyn accent.