A deranged Long Island woman is facing up to 25 years behind bars for tossing a homemade dynamite stick at her sleeping boyfriend — whose hand was blown off as he tried to get rid of the explosive, officials said.

Keyonna Waddell, 35, was found guilty Friday on charges stemming from the March 2024 incident that turned violent after the two got into an explosive argument, the Suffolk County District Attorney’s Office said.

“Domestic violence can escalate to deadly levels, and this case is a sobering reminder of that reality,” DA Ray Tierney said on Friday after the guilty verdict.

Waddell had threatened to use dynamite against her then-boyfriend multiple times in the months leading up to the incident, but he never expected his lover to follow through on the threat, the DA said.

The pair both left the the unidentified victim’s apartment after their March 22, 2024 argument but he eventually returned and went to sleep, according to authorities.

That’s when Waddell threw the explosive device into his room, officials said.

The boyfriend woke up a little while later to a “hissing sound” and then saw a flame on the floor that he couldn’t put out as time ticked away, police said. He tried to pick it up and toss it outside — but the makeshift bomb exploded and blew apart most of his hand, police revealed.

He stumbled out to the driveway screaming for help and spotted Waddell fleeing the scene, the DA detailed.

He was then rushed by responding police to Nassau University Medical Center, where the remainder of his hand and part of his arm were amputated, officials said.

Waddell was arrested just one day later and found guilty of assault, and multiple criminal weapons possession charges on Friday.

The deranged bomber is due back in court for sentencing on May 27.