By all accounts, he was an ‘energetic and happy child’ in his earliest years, per A&E, full of life and promise.

But something changed.

Shortly before his fourth birthday, the little boy underwent double hernia surgery. His family noticed an immediate shift in his personality.

The energetic, bubbly child became notably subdued and withdrawn. At elementary school, teachers described him as quiet and timid, often detecting signs of abandonment as his father’s studies kept him away from home and his mother suffered from depression and hypochondria.

The behavior escalated. He began collecting roadkill, dissecting the animals and burying them beside the hut, occasionally placing skulls atop makeshift crosses.

In one disturbing incident at age 15, he decapitated a dog’s carcass, nailed the body to a tree, and impaled the skull on a stick.

In high school, the once-quiet boy became known for bizarre pranks his classmates, bleating and simulating seizures for attention.

But beneath these antics, darker compulsions were forming.

By age 14, he had begun drinking heavily, frequently concealing liquor in his jacket at school. He told a classmate the alcohol was ‘my medicine, per the New York Times.

His parents’ marriage deteriorated further, culminating in a bitter divorce.

By May 1978, when he graduated high school, his mother had moved out with his younger brother, leaving the 18-year-old alone in the family home.

Just three weeks after graduation, on June 18, 1978, the young man picked up a hitchhiker and committed his first murder.

Over the next 13 years, he would kill 16 more young men, dismembering their bodies and, in some cases, consuming their remains.

His crimes involved necrophilia, cannibalism, and attempts to create compliant ‘zombies’ by drilling holes into victims’ skulls and injecting acid into their brains.

He was finally arrested on July 22, 1991, when one of his intended victims escaped and led police back to his apartment.

Inside, authorities discovered photographs of dismembered bodies, severed heads in the refrigerator, and a macabre collection of human remains.

That little boy who once played innocently with ‘fiddlesticks’ grew up to become Jeffrey Lionel Dahmer, the Milwaukee Cannibal, one of America’s most notorious serial killers, and subject of the first series of Netflix‘s Monster.

He was beaten to death by a fellow inmate on November 28, 1994, at the age of 34, per Biography.com.