Diva Overload! Pop goddesses Mariah Carey and Rihanna were to cool to be photographed — or even seen — together during Mariah and husband Nick’s annual All Hallow’s Eve Bash at the M2 Ultralounge in New York City last weekend.

On-site spywitnesses tell The NY Post’s PageSix Column that MC and Ri-Ri — who came dressed as an angel and a tiger, respectively — worked overtime to outdo one another at the star-studded event, which featured a guest list includinng Ne-Yo and urban supercouple Ice-T and Coco.

An informant tattles: “It was Mariah’s party, but Rihanna didn’t want to be seen with her. And Mariah was not going over to greet Rihanna. Mariah needed six guards to clear a path to the bathroom so her wings wouldn’t be dislodged.”