The incident happened Thursday morning on the 6000 block of Woodland Avenue.
Detectives released surveillance video of the suspect chasing two terrified victims.
Authorities say he slashed one of the victims in the head and the hand then drove off in a black sedan.
No word if the suspect got away with anything.
Anyone with information is urged to contact Philadelphia Police at 215-686-TIPS (8477), text a tip to PPD TIP (773847) or through PhillyPolice.com.