Inverted spear of heaven 3D model

Inverted spear of heaven from Jujutsu Kaisen but with a long stick.

This weapon resembles a naginata, which is a traditional Japanese pole weapon. A naginata typically features a long, curved blade mounted on a wooden shaft. The one in your image appears to have a unique blade design with two parallel blades, which is not typical of traditional naginata but could be a stylized or customized version.