You must be playing on the map Lockdown in a private match with free spectating enabled. Once you're spectating, head over to the Gallows (west side of the map) and there will be a large building on your right when facing the gallows.

You can NoClip through one of the top windows, and you will then be in a room with a giant teddy bear that is holding two golden Desert Eagles.

This is a nod to all previous Infinity Ward games where teddy bears can be found throughout the levels; however, this time they've taken it one step further. The reason for the teddy bears is because one the developers' daughters died of cancer while holding a teddy bear. There are mugs in MW3 with her face on them.