Gilbert the Gooey
From the Super Mario Wiki
Gilbert the Gooey is the main boss of World 1 of Yoshi's Island DS. He is a regular Gooey Goon that Kamek enlarges with his magic; twenty colorful spheres surround his body. To defeat him, Yoshi must destroy all the spheres by eating them or knocking them off with eggs. Gilbert's only attacks are swinging from side to side and moving up and down quickly. When defeated, he turns red and enlarges while fading away.
Although unavailable initially, Yoshi with Baby Donkey Kong can easily defeat him, since eggs thrown explode on contact.
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