"Bartholomew Cubbins" is a character from the children's book "Bartholomew and the Oobleck," written by Dr. Seuss. He is a young boy who lives in the kingdom of Didd, where he serves the king. Bartholomew is known for his curiosity and bravery, which lead him to confront the challenges posed by the magical substance called Oobleck. In the story, Bartholomew discovers that the king desires a new type of weather, resulting in the creation of Oobleck, a sticky green substance that causes chaos. Through his adventures, Bartholomew learns important lessons about responsibility and the consequences of one's wishes.