Oscar Pistorius -- Walks On Stumps In Court ... I Deserve Mercy (PHOTOS)

In a move that shocked a South African courtroom, ex-Olympic sprinter Oscar Pistorius removed his prosthetic legs in court Wednesday -- and walked around on his stumps.

The move was reportedly to show that Pistorius is a vulnerable man who deserves leniency in the resentencing for the 2013 shooting death of his ex-girlfriend, Reeva Steenkamp.

Oscar's lawyer told the courtroom he was "embarrassed" and "ashamed" by the demonstration -- but felt is was necessary ... especially since he's looking at a possible 15 year prison sentence.

Pistorius was previously convicted of manslaughter -- and is living under house arrest as part of his 5 year prison sentence. But the conviction was overturned last year by an appeals court, which upgraded the conviction to murder.

Pistorius is currently in the sentencing part of that case -- and he's obviously desperate to show why he doesn't belong in prison.