Gablou - It's a word I don't know, but my friends say it all the time

It's a word I don't know, but my friends say it all the time like it means something important

My friend texts me: 'Gablou bro, you look like a mess' and I have no idea what that means

At school, someone yells 'Gablou!' and everyone laughs, but I'm confused

My mom says 'You're being Gablou again' and I have no clue what that means