Subway's tuna melt is INSANELY tasty. But a new lawsuit is claiming that that ain't actually tuna they're stuffing into your $5 footlong.

A class-action lawsuit filed last week in Northern California alleges that what Subway Restaurants is calling "tuna" is actually "a mixture of various concoctions that do not constitute tuna, yet have been blended together by [Subway] to imitate the appearance of tuna."

Soooo what the heck is it?

They don't actually say what they think the fake tuna is, which is... slightly unnerving.

But they go on to add,

"Defendants have engaged in economic adulteration by selling a food product that partially or wholly lacked the valuable constituents of tuna, and that had been substituted in part or whole."

And what's Subway's response to all of this?

"Tuna is one of our most popular sandwiches," the spokesperson said. "Our restaurants receive pure tuna, mix it with mayonnaise and serve on a freshly made sandwich to our guests."

It's tuna.

(with mayo)

I guess we'll have to let the courts decide. Or if you're a brave soul, just let your taste buds make the decision.