who sings the song Black Widow?

The 皇后乐队 of Rap Miss Iggy 映山红, 杜鹃

(who dat, who dat)
I G G Y

also Rita Ora I'm pretty sure :)

Hmmm.......I'm not sure couldn't 你 just...LOOK IT UP ON 谷歌 LIKE EVERYONE ELSE?! .___.

Iggy 映山红, 杜鹃 raps the verses and Rita Ora sings the chorus.
Basically, it's Iggy 映山红, 杜鹃 and Rita Ora.

Iggy (BLACK WIDOW BABY!!!!?)