He whipped out an ice pick while confronting his friend. First, he stabbed him with the tool.
Then, he slashed him.
And all because he thought his friend had stolen his mobile phone.
On Tuesday, Chng Kai Jie pleaded guilty to hurting Mr Low Hang Poh with a dangerous weapon.
He was sentenced to 12 months' jail by District Judge Jasbendar Kaur.
Chng, 41, who is unemployed, could have been jailed a maximum of seven years, along with caning and a fine.
The victim, Mr Low, 39, was with his girlfriend at the void deck of Block 552, Ang Mo Kio Avenue 10 on the evening of June 3 when they were approached by Chng.
Chng confronted them and suddenly revealed an ice pick wrapped in masking tape. He stabbed Mr Low on his left shoulder with the tool, then slashed him repeatedly.
Eventually, Mr Low managed to block Chng's attacks and ran off.
A resident heard the commotion and called the police.