Tiana's Bayou Adventure turned into a real-life splashdown for one teenage Disneyland visitor ... who ended up in the hospital after hopping out mid-ride and falling down the famous 50-foot waterfall. A Disneyland source tells TMZ ... on Sunday ,  a 13-year-old guest exited the log ride just before the huge drop at the end of the attraction. The boy slid down the steep drop on his own ... and we're told as a precaution, he was transported to a local hospital, where he was evaluated and released.