It appears to be a reworked WWII era bayonet for the M1 Garand rifle.
Aside from it being heavily chromed, the grip plates are not original,
the crossguard has been removed, and the slot on the backstrap
has been filled in. The scabbard has also been heavily refinished.
It looks like it's a theatrical/movie prop, possibly...............
Kutmaster bought ALL of the M1 rifle bayonets and carbine bayonets and M3 fighting knives at wars end. This means everything from un started blanks to unfinished bayonets. That's why you find blades like this which has no mortise slot for the bayonet lug. The quillion wasn't mounted either. They were usually cut to knife length and chromed or polished bright. They were then sold to fill the desperate shortage of knives at war's end. Most were marked with the KUTMASTER name but not all. Their scabbards vary. They were NEVER a military item. This is one of them. The scabbard is an afterthought by someone.