Detonator

The Detonator is an Emblem Heartless that is found in Kingdom Hearts 358/2 Days.

Kingdom Hearts 358/2 Days

 * Twilight Town
 * Halloween Town

Kingdom Hearts 358/2 Days
These large versions of the Minute Bomb act similarly, but produce a much broader blast when they self-detonate. ''They also won't stagger from regular attacks, making them a dangerous foe. Take ample care when facing them.''

Strategy
The Detonater has the highest defense among the other 'Bomb' Heartless and counts down more frequently. The explosion it makes is also the biggest, so it is best to attack it from afar. Also note that freezing a Detonater while it is counting down will freeze the countdown.