Ezlo

Ezlo is Link's main companion in the Game Boy Advance title The Minish Cap. Not only does he give hints at the ready by pressing Select, but he also gives Link the power to shrink whenever he nears a Minish Portal.

Quote from The Minish Cap Ezlo (Cap) figurine: "A strange creature that looks at first like a cap. He speaks roughly and treats Link like a child, but he actually really likes Link." 

History of Ezlo
Ezlo was a former renowned Minish craftsman and master to his apprentice Vaati, who was working on a grand project: To make a cap that would grant the wishes of its wearer. No sooner had he finished the cap, then did Vaati steal it from his work desk and place it onto himself. Vaati used the power of the cap to make himself into what he claimed to be the "most powerful sorcerer".

Ezlo attempted to stop Vaati, but was unsuccessful. Vaati was able to, again, use the power of the wish-granting cap to tranform Ezlo into a green hat in the shape and likeness of a bird. Soon enough, our hero would find Ezlo in the Minish Woods being attacked, and befriend him for the entirety of a large adventure.

Ezlo's Abilities
While in a cap form, he has little power. His only abilities are giving information and hints to Link spontaneously and on demand, as well as giving background about the current situation. He can also shrink Link down to Minish-size when he stands on top of a Minish Portal, such as a Tree Stump, or a rock. He can be used like a parachute, like the deku leaf on The Wind Waker. This can only be done when you jump on a tornado.