TV host and Pussycat Doll Nicole Scherzinger spits hot fire against "Get Out" funnyman Lil Rel Howery; an unprecedented 5-on-1 takes place when singer Charlie Puth takes on every single member of the Backstreet Boys.

It's a "Big Bang Theory" rap battle as co-stars Mayim Bialik & Kunal Nayyar go rhyme for rhyme, while High School Musical princess Ashley Tisdale challenges Nick Lachey to a battle you never knew you wanted.