Yukkles wears navy blue overalls over an orange long sleeved shirt. He also wears orange and teal shoes, a teal collar, and a teal cap. He has dark brown hair and wears clown makeup.
Yukkles gives you the following puzzles in Professor Layton and the Miracle Mask:
Prologue: The Dark Parade
After the petrification miracle is performed by the Masked Gentleman, all the surrounding people try to escape in a hurry, including Yukkles. Professor Layton and Luke bump into him during his escape, and they ask him to remain calm.
Chapter 3: The Battle of Monte d'Or
On their way to the One-Ring Circus, Professor Layton and the group find Yukkles outside the Dromedary Hotel, and they recognize him as the person who they encountered during the petrification incident the previous night. He tells them he was on break and had done his back in while climbing out of the circus' clown car, and so came to the hotel to relax with a puzzle. After Layton helps him out, he decides it was time for him to return from his break.
Chapter 5: Miracles Unmasked
Yukkles is found at the entrance to Pumpkin Park, and Luke recognizes him as the clown they had seen on the night of the petrification incident. Yukkles tells them he had been having nightmares about the stone statues chasing him ever since that night, and Professor Layton assures him they intended to catch him that night at the funfair. Yukkles gives the three a free week pass into the fair, and stated he would be taking the Monte d'Or tram out of the funfair if they failed to catch him.
In a special episode, Yukkles lets Tyrone know that his food wasn't in the food tent, and this made Tyrone realize straight away that Stumble had taken it. This reminded Yukkles that he had seen Stumble eating pudding earlier, and he knew he was in for it.
Chapter 7: The Reunion Inn
Yukkles complains about how tended to hurt after his shows, and wasn't able to perform for the children any longer. Emmy suggested he did yoga before going to bed, but he makes up the excuse that he couldn't reach his toes. She then suggested he goes for a jog, but he gives her a puzzle before she can give any more suggestions. He tried to stray off the topic afterwards, but she hears him under his breath saying he was glad to get her off the topic, to which he then mumbles that he couldn't wait to get back on the ball.
"His balancing ball act may be a hit, but old Yukkles isn't the barrel of laughs he's cracked up to be. For all his top-notch performances int he ring, he'll moan and whinge about his bad back and chronic rheumatism whenever he gets half a chance."