Sam raised his brow watching Castiel, who at the moment was resting his chin on the folds of his hands. He was currently having a staring-eye contest with their new resident.
A guinea pig.
Named Sam.
He didn't know why Cas named the creature after him, but this animal was now Castiel's new companion. He spoke to the animal often. Though the name confusion was a bit frustrating until Cas decided if he was talking to the guinea pig, he'd say, "Little Sam" while the man himself was labeled "Big Sam."
He didn't really have the heart to argue because of how proud Cas looked. He just stroked the top of the guinea pig's head who let out a soft squeak.
"He likes that." Was the response.
So yeah, there were two Sam's and Castiel currently residing in the bunker.
A man.
An angel.
And, a guinea pig.