Rihanna [1] got in the Halloween [2] spirit on Friday when she dressed up as a sexy Teenage Mutant Ninja Turtle for a night out in NYC. The singer wore an elaborate costume as "RIHphael [3]" (or Raphael, Rihanna-fied) to join her girlfriends who wore similar ensembles. The look clearly put Rihanna [4] in a fun mood as she and her pals posed for photos and fans on the street before heading into a private All Hallows' Eve bash. The look was slightly more covered up than the revealing gown she wore at amfAR's LA gala [5] on Wednesday night. Keep reading for more snaps from Rih's Halloween night, and be sure to check out all the celebrity costumes this year [6]!