It even had a name: "Freddy."
Police say the name was given to the brain by Joshua Lee Long, who is already incarcerated by Cumberland County in connection with a string of burglaries in Pennsylvania, according to the Sentinel.
Police think the brain was also stolen.
Cumberland County Coroner Charley Hall has confirmed the brain as belonging to an adult human.
Pennsylvania state trooper Bob Hicks told WPMT that investigators think the brain was originally used for teaching purposes.
"At this point now, we're just trying to figure out where it came from," he said. "We're hoping that if anyone feels like they're missing a human specimen brain, bring it to our attention and maybe we could return it to its rightful owner."
Police said the brain was discovered by Long's aunt while she was cleaning the trailer-home, according to NBC affiliate WGAL. The station reported that she contacted her nephew in prison to ask about the brain and he told her that it belonged to him. At some point, she contacted police and told them about the brain, according to the Associated Press.
"The defendant related that he knew it was illegal to have the brain and that he and (another man) would spray the embalming fluid on 'weed' to get high," Trooper John Boardman, an investigator involved in the case, wrote in court documents cited by the AP.
The 26-year-old Long - currently at Cumberland County Prison in lieu of a $100,000 bail - faces new charges in connection with the stolen brain: misdemeanor abuse of a corpse and conspiracy to commit abuse of a corpse, the Sentinel reported.
Spraying or soaking marijuana with embalming fluid is "an emerging drug trend," according to a statement from the Drug Enforcement Administration. Embalming fluid is often found in morgues and funeral homes, but the fluid - which has serious health risks - can also be purchased directly from chemical companies or online, the DEA notes.
"Embalming fluid is a compound of formaldehyde, methanol, ethanol and other solvents," the statement says. "The percentage of formaldehyde found in embalming fluid ranges anywhere from 5 to 29 percent. The percentage of ethyl alcohol, the psychoactive ingredient found in alcoholic beverage, varies anywhere from 9 to 56 percent. According to the Office of National Drug Control Policy, it is common for marijuana to be laced with PCP and/or embalming fluid, both of which produce a hallucinogenic effect. Cigarettes soaked with embalming fluid trend to burn slower, thereby increasing the chance for a prolonged high."
Reactions to the drug appear to vary, with users reporting "anger" and "paranoia" as well as an "increase in women's sexual appetites," the DEA added.
While authorities may have encountered formaldehyde-laced marijuana, using a dead person's brain for drug purposes shocked some investigators.
"This is one of those situations where, I think, a lot of guys were surprised," Hicks said.