Adhesive X was a chemical created by Baron Heinrich Zemo.
During the HYDRA occupation of Castle Zemo, Arnim Zola informed Baron Heinrich Zemo that he had thoughts on how to improve Adhesive X, a personal project that Zemo had labored on for some time. While keeping his expectations realistic, Zemo heard him out.
Unfortunately for Zemo, Zola and his leader, the Red Skull, orchestrated an "accident" in an attempt to kill him. While he was left permanently scarred, Zemo vowed that his revenge would be fearsome to behold.