I came across this brick while sorting some Lego I purchased. It's similar to an Electric, Light Bulb Cover (colored globe), but with three major differences. It is a bit wider, the lower lip is a bit higher, and rather than being mostly hollow (to receive a bulb) it is designed to receive a bar. I was unable to find the part when searching Bricklink's trans-red part list.
The inside has what appear to be a part number of 10780 and a mold identifier of 1-8. Given there is no Lego stamp I'm guessing it is a knockoff, but I'd like other opinions as I'm unsure whether prototype bricks are all marked. Given the source of the parts there is a small chance it is a prototype.