This item is found only in the mobile and console version(s) of Terraria.
The Tonbogiri is a console & mobile exclusive Spear that does 50 melee damage, has very fast use speed/time, strong knockback, tier 5 rarity, is crafted at a mythril anvil, and sells for 40 gold. Requiring 1 Gungnir, 15 Adamantite Bars, and 15 Soul of Blight, this spear is very expensive. Before 1.2, it was a light blue recolour of the Gungnir.
On iOS, it has the older recipe but the newer sprite, even though iOS has 1.1.
The Tonbokiri (蜻蛉切?) is one of three legendary Japanese spears created by the famed swordsmith Masazane Fujiwara, said to be wielded by the daimyō Honda Tadakatsu. The spear derives its name from the myth that a dragonfly landed on its blade and was instantly cut in two. Thus Tonbo (Japanese for "dragonfly") and kiri (Japanese for "cutting"), translating this spear's name as "Dragonfly Cutter/Cutting spear".
The Tonbogiri is now the most expensive item to reforge, requiring 2 for plain reforging.