... 'cause it's never been seen before.

The GaGa poked her head through a horse's tail and plopped its scalped mane onto her head and off she toddled off to London's Roundhouse last night.

There she was met with her legion of her "monsters", whereupon one of them presented her with a portrait bearing the likeness of Frankenstein's bride.

Today, the photos are all over the tabloids.

That's about the size of it.