HIDEOUS!

Martin, a questionable water sanitation worker, finds a strange, fleshy organism in a water treatment tank and contacts Belinda Yost, seller of animal and human oddities at International Medical Specimens Inc. (IMSI). After speaking with Martin, Yost rushes out excitedly. She tells Elvina Shaw, her incompetent receptionist, to arrange a meeting with Mr. Napoleon Lazar, a high level corporate executive. Instead, Elvina calls Dr. Emilio Lorca, another oddities buyer, who pays extra for an exclusive “first look” at her new specimens. Elvina tells him Yost's plans. Lorca talks with his assistant, Sheila. Together they plot against Yost and Lazar's treachery. Yost meets Lazar in the cold storage level of IMSI, pays off Martin for the item, and secures a deal with Lazar: a check for $650,000 and a signed contract to spend a minimum of $200,000/year with her for the next 10 years.

On his way home, Lorca has Sheila ambush Lazar. She wears nothing but a miniskirt and a gorilla mask. Handcuffing Lazar to a tree, she steals the specimen, Sheila brings it back to Lorca's castle and into his study. Lorca places it in a jar with preserving liquid. He then places the jar on a shelf, with 3 other oddities. They are a few amongst many other grotesque creatures in jars. Sheila meanwhile destroys all evidence in an “acid bath” trapdoor within the castle. While Lorca dozes, the newest specimen reanimates the other 3 specimens. The new specimen is revealed to be an organism with an enlarged human head, deformed with two pairs of eyes and two mouths, one on top of the other, and a short torso. It sprouts several tentacles. The other 3 specimen include a large blob with a face sunken into its folds;, a stocky, brutish, muscular creature resembling a hairless ape; and a gaunt, skeletal creature with porcupine-like spines for hair.

Later, Lazar Yost, and Elvina seek out PI Leonard Kantor, to find the thief. After a few minutes of pressing Elvina, she admits to them that she informed Lorca about the sale. They go to Lorca's castle and Lorca strikes a deal with Lazar. Lazar questions the authenticity of the doctor's collection. Lorca bets that if he can impress Lazar with his collection, Lazar must agree to let him keep the specimen. Lazar agrees, and is initially impressed. When they enter Lorca's private study, they find the 4 jars broken and the specimens gone, leaving tracks to a vent shaft. Lorca locks down his castle with a special security system, while Sheila holds the four at gunpoint.

After no one will confess to taking the specimens, Lorca locks them in a closet and goes to search the castle. A tapping on the wall draws the prisoners' attention. Talking through the wall, they are able to guide “the tapper” (the specimens) with yes or no questions into prying open the locked door. Lorca returns and the four specimens are finally revealed to everyone.

When Yost goes to gather the specimens, she falls on the skeletal creature and is stuck with its spine-like hair. Meanwhile, the hairless ape creature attacks Sheila. The blob grabs the gun and shoots at the humans. They barricade themselves in a bedroom, for some time. Elvina is sleeping on the bed when the hairless ape creature sneaks under her blanket and begins breast feeding on her. She wakes and panics, running out of the room. She then trips and falls over a balcony railing to her death below.

The remaining five go below in search of the creatures. Lorca and Lazar each try luring the creatures, but they run off causing. The two men then face each in a sword fight. Yost triggers a boobytrap while trying to escape solo and is impaled. Lorca and Lazar's sword fight moves over the acid bath trapdoor. The hairless ape creature presses the button, causing both men to fall and dissolve in the acid.

Sheila uses the security override keycard to lure the specimens out onto a carpet, then uses the carpet to sweep them into the open acid bath. Sheila and Kantor leave in his car. They fail to see the bloody tracks leading up the ladder and out of the acid trap. As they drive off, the creatures are seen through the trunk's keyhole.

The four specimens escape their jars, and after a series of confrontations, Yost falls onto the skeletal creature and is impaled by its spines.

The film's ending delivers poetic justice to the greedy collectors, as their lust for bizarre trophies ultimately leads to their undoing by the very oddities they sought to possess. The climax underlines the darkly comic message: in this world of grotesque obsession, the real monsters are on both sides of the glass.