Help identifying utensil spear
This is an official LEGO piece. It is called 57467a Minifigure, Weapon Harpoon, 4 Grooves in Shaft and has been produced for almost 20 years, appearing in 37 sets.



Chrome Silver is the common color, Flat Silver (the one on the left in the picture) is the rarer color, only appearing in 1 set - 70800 Getaway Glider from The LEGO Movie - but this piece is still cheap on BrickLink, so no real value increase despite its rarity.