Komushi (コムシ, Komushi) is a human puppet used by Sasori while he was still living in Sunagakure. The puppet was made out of the corpse of Sasori's only friend Komushi after his death. There is no clear evidence but it is suspected that Sasori was responsible for Komushi's death so that he can make the first human puppet.
The puppet's left arm could extend a hidden blade from the palm to strike at the enemy with a quick stab.
It likely maintained the same mechanism in its right arm from when he was alive.
Since Komushi's right arm and part of his chest were shown discoloured from accidentally poisoning himself, it is likely the corresponding areas on the puppet also have poison.