means seriously or for seriously, used during sarcastic remarks and regular conversations.
"The other day Jenna was all like "I ate food for breakfast" and I was like "No. . . Fercereal?"
Lilly- "Tony and Sarah are dating!"
Kara- "No way! are you Fercerial?"
For real; Really; Serious
Are you fercereal?
Oh, I'm fercereal