Watch Lin-Manuel Miranda Rap On The Spot In Jimmy Fallon's Wheel Of Freestyle

He saves the best for last.

Lin-Manuel Miranda stopped by The Tonight Show Tuesday night ahead of his SNL hosting gig this weekend. Jimmy Fallon couldn't help but challenge him to a game of Wheel of Freestyle against Tariq (aka Black Thought) from The Roots. Each of them is given three words or phrases that they have to work into a freestyle rap.

Lin-Manuel starts things off with the words "robot," "corn maze," and "Harry Potter." He doesn't quite mention Harry Potter specifically, but you really have to give him credit for finding something to rhyme with "expelliarmus."

Tariq is next up with "guacamole," "lumberjack," and "Super Bowl." He doesn't miss a beat, and even Lin-Manuel can't help but praise his skills, asking, "Why am I here?"

The answer to that question becomes obvious in the next round, as he gets a little NSFW in rhyming "election" with "erection." As he eventually explains to a stunned Jimmy, "I have an erection to vote."

See Lin-Manuel in action in the video below:

Speaking of election day, Lin-Manuel also premiered his new voting PSA during his appearance. The video features the cast of his upcoming documentary Hamilton's America, including Hamilton performers such as Renee Elise Goldsberry and Daveed Diggs, as well as politicians like Elizabeth Warren and President Barack Obama himself.

"If you're inspired by Hamilton, if you're inspired by our founders," Obama says, "understand that the system of government they designed only works if you participate."

Watch the full video below: