Possible Clues:

• River ending at Yuma
• -- monster, a venomous beaded lizard
• River that ends at Yuma
• It flows into the Colorado near Yuma
• ___ monster (certain lizard)
• Colorado feeder / Sacha Baron Cohen character
• River that meets the Colorado at Yuma
• River that joins the Colorado near Yuma
• Monster that's really a lizard
• 'Monster' that's a lizard