Oomis- close – it’s Shach (Sheik/King) Mat (dead). Mat is dead in Arabic. Similar to Meit מת in Hebrew. That’s why Israelis and Arabs today call Chess “Shachmat”. And Chess is probably just an Anglicized version of Shach.
With all due respect to Rav Shachter, he should see the Sefer Nisuin K’Hilchasam 11:221 in the name of Rishonim that Krias Kesuba is done by chashuv Rabbonim. Not monkeys…