Milt

Milt is a colossal, conniving bird who's feathers just so happen to be the cure for Tamaranean Flu. The Teen Titans visit him to help heal Starfire in the comic "Starfire Starter", but

History
When Robin sees that nothing is working to heal Starfire of her illness, Raven offers to transport the team to the ancient world of Glibshars: gigantic birds known for their cruelness, but ALSO for their curing feathers. Robin likes the idea, so Raven teleports them to a rocky landscape. They immediately happen upon Milt, a saggy-skinned vagabond who's got info on the Glibshars. He tells the Teen Titans that the birds are all gone, but he can part with one of his treasured feathers so long as they help his family with chores around the camp.

The Titans agree to assist him, but, unbeknownst to them, Milt is actually one of the ancient Glibshars—he and his family's feathers have been plucked clean from their bodies, but he's got a plan to get them back... The Titans eventually put together a pot of soup. But before the team can get their feather, Starfire accidentally blasts one of her fiery sneezes at Milt. His hat burns off, revealing charred feathers. Cyborg and the others realize Milt is a Glibshar, but by then, it's too late. The giant bird and his family end up eating the Titans, restoring their feathers and size.

Characteristics
Years of foreigners coming for Glibshar feathers have left Milt with barely any left; his pink skin is completely exposed, making him unrecognizable to feather scavengers. Even his beak has turned into a fleshy mass somehow. To keep what dignity he has left, Milt wears a ragged pair of brown pants (matching his brown eyes, and he's often seen wandering around sporting a sign that says "ASK ME ABOUT THE GLIBSHAR." To conceal some feathers he has left on his head, he wears a simple bowler's hat.

After eating the Teen Titans, however, Milt's yellow feathers start growing back in abundance. Soon, he is looking like a true Giant, Gold-Crested Glibshar. His beak also starts to heal, turning hard and brown. And, while Milt was fat before dinner, he's now got a pretty big belly.

Teen Titans Go! Comics

 * "Starfire Starter"

Trivia

 * Milt only starts to look sort of like a bird when the Titans realize he's really a Glibshar. Before that, his beak was barely recognizable, and the feathers on his arms weren't defined at all. This choice in artistry was likely done so as to not reveal he was a Glibshar to the readers to soon.
 * In Raven's ancient volume, the picture of a Glibshar depicts them as having bird wings, and yet Milt and his wife and son have more hand-like appendages. It could be that their feathers just need to grow back, though.
 * It's unknown where exactly Milt and his family live. Raven describes it merely as the "Glibshar's Homeworld."