Flying Thunder God Kunai

The Space-Time Kunai are special Kunai utilized by Minato Namikaze to use his Jikūkan Ninjutsu the Flying Thunder God Technique. They look like a standard kunai except they have three blades instead of one and on the handle is the "formula" for Minato's teleportation ability. He seemed to prefer using these special kunai over the standard kunai.

Trivia

 * It is implied that touching the kunai activates a Jikūkan Ninjutsu like Minato did to the Nine-Tailed Fox Menacing Ball with a Space-Time Barrier