Just Wanna See You Smile

 is a song sung by Phineas. It was written as part of the promotion of Phineas and Ferb "Listerine Smart Rinse" line of products. It can be downloaded in Listerine's website, if you enter the secret redemption code and the last four digits of the UPC from specially marked bottles of Phineas and Ferb Listerine Smart Rinse, on sale at Walmart.