You are in the Nether. You find yourself face-to-face with this monstrosity. You offer it some warped fungus, but it's no use. It shoots a fireball ball of fungus at you, and you perish. He then takes the warped fungus, and leaves.

And this is totally a strider, and not a ghast. Totally. Don't even think about calling it a strider, or he will visit your profile page.