From Wiktionary, the free dictionary
so help me cat
- Euphemistic form of so help me God
1920, George Sargant, The Winding Track, page 45:"So help me cat," Snowy chuckled, "he shut up like an oyster, and in his confusion he said, 'Good afternoon, Mr. Snowy,' and he never came again."
2010, Brian David Bruns, Cruise Confidential: A Hit Below the Waterline, page 466:"ANY BASTARD IN LINE BEFORE ME WILL BE BEATEN TO DEATH AND THROWN OVERBOARD, SO HELP ME CAT!"
- John Camden Hotten (1873) The Slang Dictionary
