The Grumpy Old Troll (also known as Mr. Troll) is the secondary antagonist of Dora the Explorer franchise. He's a troll who lives under the Troll Bridge that Dora and Boots sometimes come across. Whenever they tries to cross his bridge, he will jump out and sing a song telling them that they need to answer a riddle or else they will not be allowed across.
He has got a yellow body with long orange beard and an orange mustache. He has white eyes with black pupils. He doesn't wear clothes at all. He's almost always mad, evil or angry. He enjoys making up riddles for visitors who try to cross his bridge. Sometimes, he's willing to kill guys who tries to get over his bridge without solving the riddle, or guys who can't solve the riddle. However, he is shown to be happy at times and does have a few hobbies.