Arrow keys to move Yoshi, WAD to move Scratchy. try not to get hit by Bowser or the arrow! Counting is very important in this case. You have 5 tries or less (depends on how fast you get to him) to hit Bowser, and he has 25 HP.
Thanks to @Ciaran33X33 for Yoshi sprite, and @juliangamer524 for music. @wertyuhjnbvf for bowser sprite. To beat this, you must be an expert at maneuvering!