Rihanna Is Sexy Pebbles Flintstone at Niece's Birthday Party

The singer dressed up as one very sexy Pebbles for her niece's Flintstones-themed birthday party. "They call me ratchet Wilma," a friend declares in an Instagram video dancing with Riri. "And this is naughty Pebbles."
Clearly a very exciting child's birthday party.  Watch the video!