I meant my other Grandma
You use this phrase when you’re too dumb to remember which grandma is dead and which one is not. It’s like you’re trying to blame two grandmas for one lie, and both of them are probably mad.
I said my grandma died, but I meant my other grandma who was still alive and had a phone.
I told my friend my grandma died, but she was just watching TV.
I blamed my grandma for my bad math test, but I meant my other grandma who was eating ice cream.