The Hedgehog is Chikusa's main weapon. It is a pair of red yo-yos with long and thin strings. Its disks are butterfly-shaped and are embedded with the letter "K". The disks itself are edged, and, combined with Chikusa's expertise, gives the yo-yos a high killing ability.
The holes in the yo-yo are capable of shooting numerous poisonous needles. The needles are used in Chikusa's attack, "Needle Shower". The strings are also harmful, as Chikusa was able to slice Gokudera's dynamite sticks with them. Ten years in the future, Chikusa is also able to cover the needles in Rain Flames.