It's like one of those riddles, except real and very sad.

"Gotta love NYC...casual dead shark on the subway," Instagrammed user bsanchz after spotting the deceased animal on a Queens-bound N train late last night.

A rider who saw the shark firsthand wrote in to Gothamist to say it is definitely the real deal, but they didn't see who put it there.

With it being Shark Week, some are calling foul — not just over the odor, but also the smell of a viral campaign.

But, c'mon. Even Discovery wouldn't sink that low.

An MTA spokesman released a tongue-in-cheek statement to Gothamist saying the shark's remains found on its trains "are handled by Shark Maintainer Is, or if none are available on that shift, then by Aquatic Mammal Handler IIs."

Sharks aren't mammals.

UPDATE: For what it's worth, The Discovery Channel formally denied any ties to Subway Shark:

Shark Week is about conservation, so it deeply saddens us that someone would thing that this was funny or in any way connect to our celebration of sharks.

[photos via bsanchz, imababysquid]