Scratch was a member of the Shoal of the Winter Harmony. On behalf of the Shoal, he met River Song and the Twelfth Doctor aboard the Harmony and Redemption to buy the Halassi Androvar. To prevent double-crossing, the Shoal had occupied the entire dining room.
Agreeing to River's terms, Scratch gave her a device concealed within his head that could transfer the payment to any bank in the galaxy. He then announced that the Androvar would honour their beloved King Hydroflax. Scratch was enraged upon discovering that the Androvar was inside Hydroflax's head, denouncing it as "heresy".
Scratch witnessed the arrival of Hydroflax's robot body and the inadvertent destruction of Hydroflax's head. He stated that he would gladly offer his own head as a replacement, and also that taking the Doctor's head would be Hydroflax's "crowning achievement". (TV: The Husbands of River Song)