The kidnapper hands are two villains in Edgy Oobi.
The kidnapper hands are two members of ISIS. In "Grampu Gets Killed by ISIS," they (obviously) kidnap Grampu. They call Oobi and say that they'll only return him if Oobi delivers a million dollars to them. They arrange for Oobi to put the cash behind Whole Foods at 7 PM, but he doesn't follow through, leading them to seemingly mind-wipe Grampu. The kidnapper hands are indirectly mentioned in "Oobi Tries Lean" which continues the storyline of the previous episode.
Like the other characters, they are two bare hand puppets. One has green eyes and no clothes. The other has blue eyes and a black robe.