Inspired by both Japanese mythology and the Nioh version. Though in nioh its more of an ooze I went with an incorporeal undead type.
“A Yokai which emerged from thrown away needles“
The Harinobo is a Yokai formed by worn-out needles and broken blades. People in Japan believed that objects used for long periods of time housed a soul within them, and called them “tsukumogami”. While these tsukumogami are not necessarily intent on harming humans, it is said that some tools harboured a grudge for being permanently discarded or being used in an improper manner, which caused them to transform into Yokai. Among them, it is thought that objects such as needles and blades are especially susceptible to becoming Yokai, so needles and blades that can no longer be used are often blessed at shrines. This ceremony is known as either hari-kuyo for needles or hamono-kuyo for blades.
Incorporeal Movement. The harinobo can move through other creatures and objects as if they were difficult terrain. It takes 5 (1d10) force damage if it ends its turn inside an object.
Maddening Slash. Melee Spell Attack: +6 to hit, reach 5 ft., one target. Hit: 17 (4d6 + 3) psychic damage.
Sword Catapult. The harinobo chooses up to three creatures it can see within 60 feet of it. Each target must succeed on a DC 15 Dexterity saving throw, or it takes 7 (1d8 + 3) piercing damage.
Pincushion (Recharge 6). Each creature within 30 feet of the harinobo must make a DC 15 Dexterity saving throw. On a failed save, a target takes 12 (2d8 + 3) piercing damage it spirit ejects thousands of old and rusty needles from its body, and it is stunned until the end of its next turn. On a successful save, it takes half as much damage and isn’t stunned.
Banner Credit: In-game screenshot, (c) team ninja.