There are many evidences that Stanford has a twin or a brother named Stanley. Stanley is probably a scientist who created the experiments in the room where Soos found.

Here are the proofs:

- At the episode 'The Time Traveler's Pig', you will see a man with glasses wearing a black T-shirt when Dipper and Mabel were time-traveling. That man is not Stan. Its Stanley.

-Grunkle Stan's car's plate number read STNLYMBL, which is Stanley Mobile.

-The glasses in the episode 'Carpet Diem', is similar to the man wearing glasses.

What do you think guys? Comment or send me a message.

[Edited]

When I watched the episode "Not What He Seems", it was a little suprising. In my opinion of course.