Chris Brown -- L.A./Vegas Halloween Parties Go Down in Flames

Chris Brown has become a Halloween nightmare for 2 big nightclubs that now have anger issues of their own ... because Brown has bailed on them.

Chris was booked to host a party at the Conga Room in L.A. tomorrow night, followed by another hosting gig Friday with GF Karrueche at Haze nightclub in Vegas.

We've learned both clubs just got word Chris will be a no-show. As TMZ first reported, the singer will stay put in a Malibu rehab joint for up to 3 months so he can deal with his anger issues.

But here's the thing. Even Karrueche bailed.

The show at Haze will go on. As for the Conga gig, the event has been cancelled.