Hitōkon

was a root-like flying yōkai that had the ability to possess other yōkai and humans. Under the influence of Naraku's tainted Shikon shard, Kōhaku followed his instruction to chase and kill it.

Manga vs Anime
In the manga Hitōkon was killed by Kōhaku while in the anime it was sliced by Kagura's Fūjin no Mai.

Hitōkon Hitokon 飞头根