A man is suing a posh Manhattan spa after a 65-pound pit bull nearly turned his 10-pound schnauzer into doggy biscuits.

The lawsuit alleges that shaggy schnauzer Diesel was left helpless at the Biscuits & Bath spa on Fifth Avenue when the larger pit bull got loose from handlers and mauled him, nearly ripping off one of the small pooch's hind legs.

Diesel's owner, Jeffrey Tullman, says his schnauzer is tough, but was "way outgunned." He is suing the spa for $200,000 in Manhattan Supreme Court.

Spa manager Jason Christmas says all customers must sign liability waivers before leaving their pets. The spa is cage-free and off-leash.

Tullman says that his dog underwent surgery and needed more than a dozen stitches.