Norman is the name that Michael Tucker gave to the marlin he hung on the wall of his office at the Burbank Buy More when he was manager of the store.
Most of the Buy More staff once believed that Big Mike actually caught the marlin himself, but in fact, he bought it on Ebay for $200, as he reveals to Morgan in "Chuck Versus the Marlin". in which Norman plays an important role.
Lizzy, the Fulcrum operative under the guise of a delivery girl, hid a bug receiver inside of it, which contained information that pointed at Chuck as the Intersect. Jeff and Lester steal Norman, and hide it at Chuck's home, where it's found by Morgan, and then hidden it the freezer of the Wienerlicious. Lizzie brakes Norman open and takes the receiver.
Norman is eventually returned to Big Mike's office at the end of the episode but he has obvious duct tape bandaging.