Listen to Red Hot Chili Peppers on iHeartRadio

Things got heated when Red Hot Chili Peppers drummer Chad Smith faced off with a Will Ferrell in a drum-off on Thursday's "Tonight Show Starring Jimmy Fallon."  

The two look-alikes got four solos each.  And even though Ferrell was obviously getting an assist from an off-camera "ghost drummer," he still won the battle when he broke out his trusty cowbell and led all of the Red Hot Chili Peppers in a surprise performance of the Blue Oyster Cult classic "Don't Fear the Reaper." 

After Fallon gave Ferrell the 2014 Golden Cowbell for his victory, Smith and his Chili Pepper bandmates teamed up with the Roots to play Funkadelic's 1974 track "Standing on the Verge of Getting It On" and their own hit "Give It Away." 

Before they got behind their kits for the drum-off, Will Ferrell and Chad Smith sat down to explain how the feud started.  But they came out dressed in identical outfits, and only made things more confusing by pretending that Chad was Will and Will was Chad. 

Ferrell joked that his Chili Pepper bandmates weren't even sure who was who anymore.  He also had a little fun at the expense of Smith's charity Little Kids Rock, saying they actually take instruments from schools rather than donate them. 

All joking aside, however, the drum-off raised $300,000 for both Little Kids Rock and Ferrell's charity, Cancer for College.