Oh my cat 

Unvoiced for Oh my God.

The /g/ sound is the the voiced cognate of the unvoiced /k/, and the /d/ sound is the voiced cognate of the unvoiced /t/, thus, articulator placement during production cat is identical to the production of the word god. God backwards may be dog, but God unvoiced is cat.

Oh my cat, what a cute houseplant.

Oh my cat by NYPopcat June 17, 2022

Oh my cat! 

The opposite of saying "Oh my God!" because God spelled backwards is dog, which is the opposite of cat. So I suppose that makes it the opposite reciprocal or some term like that. From the song "Never Ending Math Equation" by Modest Mouse.

Person 1: Hey, guess what I just got
Person 2: What?
Person 1: Front row tickets to see (Insert your favorite band here) next week!
Person 2: Oh my cat!!

Oh my cat! by Miss Muffet October 19, 2004

OMCC (Oh My Ceiling Cat) 

A term used by those 2 out of 3 lol cats that believe in Ceiling Cat and do not believe in Christianity's "God", therefore they do not use the term "OMG" a.k.a "Oh My God".

"OMCCWTFBBQ! A Capshun!" said the lol cat on icanhascheezburger.com

"OMCC (Oh My Ceiling Cat) thats one funny lol cat"

OMCC (Oh My Ceiling Cat) by Assassin Phone Inc. June 13, 2008