PK5: Pokestar Studios Prop Creatures (Studiomons) .

In Pokemon Black 2 & White 2, lies the facility Pokestar Studios, which allow players to create "films",
which is done by having users battles Props (between a pair of legs and Mecha Tyranitar),
which are not traditional Pokemon.
Fan term for these Studio Creatures/Props are known as Studiomons.

At present, the only Pokemon dumped from RAM is are(thanks @jojo12100
 

Majin		F-00		Black Door		White Door

Bringing any of these "Pokemon" out of the PC will cause it to turn into an unusable bad egg.
The only way to use it via the Battle Box feature,
but do note that none of the Studiomons have a back sprite, so it will appear as a black square.

                                       illus: Studiomons appearing as a Black Square

Presently it appears PKHeX may allow importing into a B2W2 Save (perhaps with limitations),
but if it doesn't, this programs accepts it's usage too: