Senseless Phagia

Senseless Phagia is when someone eats something because they can't tell what it is by using their five senses.

Senseless is when the senses aren't in use. Phagia means "consume."

If a person has no sense of smell or taste, so they eat dirt and thinks that it's chocolate, that qualifies, and they've committed geophagia.

This also applies when characters don't use their sense of sight while they're eating and pick up something gross and stick it in their mouths without even looking at it.

Related to Squick and Nausea Fuel and Cringe Comedy.

A subtrope of Rule of Perception.

Examples of Senseless Phagia include:

Film

Problem Child 2 has two examples: One is Junior's urinating into a pitcher and passing it off to an unsuspecting man as lemonade. The other is Junior's releasing his cockroach army into his family's dinner.
The Hitcher features a severed finger in a man's fries.
Mallrats and the "chocolate pretzel."
American Pie and the jizz in the Cappuccino.
The Lost Boys - Blood instead of wine, maggots instead of rice, etcetera.
Food Inc They're putting chemicals in our food!
Soylent Green is made of people.
The Texas Chainsaw Massacre - The theme of corporate and non-profit cannibalism is addressed on varying levels in every movie. "You could have dinner with us... my brother makes good head cheese!"

Cookoff Hostess: "You've got to tell the secret of that fabulously tasty chili!"
Drayton Sawyer: "No secret. It's the meat. Don't skimp on the meat. I got a real good eye for prime meat. Runs in the family." (the hostess bites into chipped off piece of bone) "Whoop, whoop! One of those hard-shell peppercorns!"

Minority Report has one, just after Anderton's eye replacement. The surgeon tells him that a sandwich and milk are in the fridge. Well, that much is true, but John's blind bumbling leads him to the rotten equivalents first.
Waiting... The staff of a restaurant use this as a punishment, as is showcased in the trailer
The short film known as 5:45 A.M. features a waiter doing something to the food that involves having his pants around his knees, as seen here.
Harold & Kumar Go to White Castle stop by a fast food drive-thru, where one of the disgruntled workers informs them that the secret ingredient to the food is animal semen.
In Cabin Fever 2, a custodian who shows signs of infection with a flesh-eating virus takes a leak into the punch that a girl was mixing up for the prom (yes, just to be a douchebag). Halfway through the stream, the urine turns into a stream of blood. The promgoers later remark that the punch tastes like piss, but don't seem to think it noteworthy enough to not drink the punch, apparently dismissing it as bad punch.

Literature

In Fight Club, sabotaging restaurant food is one of Tyler Durden's pastimes, which leads to this trope for the unfortunate customers.

Live Action TV

Inverted with Millennium, episode: Somehow, Satan Got Behind Me - Four demons, in their human forms, assemble in the predawn at a doughnut shop and reflect on the havoc they've wreaked on humanity. They, of course, mistreat the doughnut store clerk, who then urinates in their coffee, which they love.
One episode of Upright Citizens Brigade featured a sketch where one man claimed that color-blindness was the reason his niece couldn't tell the difference between a juicy, delicious apple and a raw, slimy pig anus. An audience member is incredulous of the claim, insisting there is something far more serious wrong with the girl if she really can't tell the difference. The first man offers him a chance to experience simulated color-blindness with a special pair of glasses and then offers him a choice of two clear ziploc bags (one with apples, the other with pig anuses):

Skeptical Man (reaching into the pig anus bag): "Oh yeah… that's an apple! OH GOD I WAS WRONG!"

Black Books: Bernard denies that he's lost all sense of taste through his booze and cigarette habits, and believes that he's eating "some sort of delicious biscuit". It's a coaster. Made of cork.

Western Animation

The Simpsons are drinking some fruit punch.

Homer: "Ooh, punch!"
Lisa: "Ew! Dad, this is blood!"
Homer: "Correction: Free blood."

From Pixar film Ratatouille...

Remy: What's that you're eating?
Emil: *smacks lips* I'm not exactly sure, to be honest.
Remy: You don't know what it is...and you're eating it?
Emil: You know, once you get past the gag reflex, a whole world of possibilities opens up!

Urban Legends

Real Life

Daniel Rakowitz of New York killed his girlfriend in 1989 and made soup with her remains that he fed to homeless people.
Coffee pee