Halloween came early this year for a man in the UK, who landed in hot water with the police after a backyard experiment went hopelessly wrong.

As detailed by The Telegraph, an amateur scientist named Harry Whittaker was arrested after police discovered a noxious blend of chemicals in his makeshift lab, appropriately located in a shed behind his mother’s house.

Whittaker’s setup was found out after he called for an ambulance after suffering from anaphylaxis, an allergic reaction he said was triggered by his mother’s potpourri. When authorities arrived, however, they discovered a veritable warehouse of potions, including black gunpowder, flash powder, firework pellets, fuses, and “lethal poisons,” as the Graph put it.

Some of the chemicals recovered even included radioactive matter, as well as white phosphorus, a waxy compound which can ignite when exposed to oxygen. They also recovered a copy of “Home Workshop Explosives,” an infamous tome by an underground chemist who goes by the moniker Uncle Fester. (His catalogue includes other works like “Secrets of Methamphetamine Manufacture” and “Silent Death,” a recipe book for creating DIY nerve gas.)

When paramedics showed up, they noted Whittaker was suffering from hives and a wheezing cough, but weren’t sure how to treat it. When they didn’t buy Whittaker’s potpourri story, he caved and brought them to his shed, which he reportedly described as “his laboratory.”

Unsurprisingly, the paramedics then called the police in, who found — on top of everything else — a baggie of heroin in Whittaker’s possession. The home chemist was then arrested and charged with making and possessing explosive substances.

During his trial, which kicked off this week, the prosecutor said first responders noted that Whittaker’s shed “did not have any ventilation system, although one window was broken.”

“He said it had occurred during a previous experiment which had resulted in an explosion,” the prosecutor continued.

According to the Graph, Whittaker was “astounded to be arrested for having an educational interest in science,” adding that his goal was to collect every element of the period table.

“I take precautions so it doesn’t harm anyone,” he reportedly told police. “I don’t make things dangerous. It’s all just harmless fun, essentially. I’m just a nerdy kid who likes doing science.”

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