He's pranked Madonna, Will Smith and Adele ... but his next victim could be his cell-mate Bubba.

Vitalii Sediuk faces jail time for crashing the Grammy Awards stage and messing with Adele's moment at the February ceremony ... TMZ has learned.

The 24-year-old Ukranian ran onstage ahead of the singer's acceptance speech and spoke into the microphone before Jennifer Lopez shooed him off. He's been charged with entering a performance area and interfering with performers ... both misdemeanors ... and faces six months in jail and a $1,000 fine for each count.

He'll be arraigned May 31.

Remember -- this is the guy who tried to kiss Will Smith on a red carpet in Moscow ... and got slapped down for it. His first trick was to hand Madonna a bouquet of hydrangeas -- knowing full well that they are the Material Girl's "most loathed" flower.

Wonder if he has any pranks involving soap on a rope.

Adele is UNDER ATTACK ...  getting blasted with fat jokes by a major celebrity looking to pick a fight ... and it was all caught on tape.

So who's the person hurling all the hatred?? It's Joan Rivers ... DUH ... didn't you read the headline?

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After the brief blip that was her Mrs. Roper Grammy getup, Adele went back to wearing her black dresses to the Oscars on Sunday.

What gal doesn't love a little black dress?

The moron who crashed the stage at The Grammys -- only to get kicked off stage by Jennifer Lopez on live TV -- was arrested for trespassing directly following the awards show ... and it's not the dumbest stunt he's ever pulled.

The idiot who wound up in handcuffs is Vitalii Sediuk ... the same dumbass who got slapped in the face by Will Smith last year (and rightfully so) when he tried to surprise the actor with a kiss on the lips on a red carpet.



During the Grammys, Sediuk somehow weaseled his way backstage ... and when Adele was announced as the winner for Best Pop Solo Performance ... Vitalii rushed to the podium and tried to grab the mic from presenter Jennifer Lopez.

Sediuk managed to get out a few words ... saying, "Thank you, Adele. You’re my inspiration” ... but Lopez quickly ripped the mic back and shooed him offstage.

Directly following the show, cops arrested Sediuk for trespassing -- and he spent the night in a jail cell ... this according to the Hollywood Reporter.

Sediuk told THR he's just a prankster and meant no harm -- adding, "I’m not a crazy guy. I just think differently."

Sure.

Doing her best Mrs. Roper impersonation, Adele looked gorgeous in a red floral tapestry at the Grammys on Sunday.

At least it's different from her usual shapeless black ensembles, right?