a- prefix - You can add 'a' to anything to make it sound like an insult

You can add 'a' to anything to make it sound like an insult or a cool name, especially if it's related to McDonald's.

My friend called me 'aMcDonald' and I was like 'what even is that?'

My brother added 'a' to 'Big Mac' and now it's 'aBig Mac' and it sounds like a insult.

My teacher said 'a' is like McDonald's and I'm confused.