The stabber has only one leg. The stabber’s lawyer has only one leg. And the guy who was stabbed? No legs.

A bizarre Manhattan attempted-murder case that could double as an amputees convention — involving two limb-deprived wheelchair-bound combatants and an ice pick in a Wards Island homeless shelter — took an even weirder turn at sentencing yesterday when the stabber’s one-legged lawyer asked to withdraw his client’s guilty plea.

At the time he pleaded guilty, Floyd Johnson, who lost his left leg two years ago to an infection, was feeling excruciating pain — in the leg that isn’t there, the lawyer said.

“It’s called phantom pain,” explained defense lawyer Norman Steiner, who lost his own left leg six years ago in a motorcycle accident.

Steiner, a veteran defense attorney and Johnson’s court appointed lawyer, caught the case purely by odd coincidence. He frequently suffers phantom pain himself, the lawyer said.

“It’s a recognized neurological condition, first noted in the literature during the Civil War” Steiner told The Post. “To my client, it felt like his leg, which doesn’t exist, was being crushed. I’m arguing that his guilty plea was not voluntary and knowing.”

Johnson had originally told cops he stabbed his shelter dorm mate out of self defense. He’d made no mention of his phantom pain back in July, when he agreed to a five-year prison term and pleaded guilty to felony assault, concedes Steiner, who was not his lawyer at the time.

“It’s the type of pain people are embarrassed about,” the lawyer said. “Most people who suffer from phantom pain think they are losing their mind,” he said.

In court yesterday, prosecutor Erin LaFarge greeted the plea-withdrawal application with skepticism, and said she will requisition all of Johnson’s medical records before responding. Manhattan Supreme Court Justice Jill Konvisor adjourned the case until Nov. 26.