Loudmouth

The Crescendo (ラウドネス), also translated as "Loudmouth" in Kingdom Hearts 358/2 Days, is an Emblem Heartless that is found in Kingdom Hearts: Chain of Memories, Kingdom Hearts II, and Kingdom Hearts 358/2 Days.

Kingdom Hearts: Chain of Memories
A hopping, horn-like Heartless.

It's a bothersome foe that can honk and call other Heartless.

Kingdom Hearts II
''It restores the HP of surrounding enemies. Use Heal Stomp with the right timing to heal the party.''

When attacked, it may call for help, so be sure to defeat it immediately.

Kingdom Hearts 358/2 Days
''These small Heartless cause the most trouble when they toot their horns to heal themselves and their cohorts. The wind missiles they shoot can be returned with a block.''

''TIP: Wind-based attacks can air-toss you. While airborne you become an easy target and will take more damage if hit.''

Kingdom Hearts: Chain of Memories

 * Wonderland
 * Neverland
 * Destiny Islands

Kingdom Hearts II

 * Olympus Coliseum

Attacks
These Heartless can be both a pain and a gain. They have little strength, but their sounds can call in reinforcements. Their sounds can also heal nearby Heartless, but by using the Reaction Command, Heal Stomp, the Crescendo's healing sounds are directed towards Sora and friends instead.
 * Healing Trumpet: Heal Heartless' HP
 * Trumpet Strike: Pounce and trumpet swing
 * Trumpet Summon: Summon Heartless

Etymology
Musically, a crescendo is a gradual increase in volume.

Trivia

 * The Crescendo, as well as the Creeper Plant and Tornado Step, are the only Heartless that were introduced in Kingdom Hearts: Chain of Memories.