From WiKirby, your independent source of Kirby knowledge.
Needle-Bomb is a Power Combo of the Needle and Bomb abilities in Kirby 64: The Crystal Shards.
By using the ability, Kirby takes the appearance of a Gordo and gains the ability to slowly hover in midair. While using the ability, Kirby can harm enemies by moving into them, though it may cause him to detonate early. After some time (or if the player presses the B button early), Kirby explodes and all eight spikes from his Gordo form launch in a separate, straight direction.
Like the other abilities in Kirby 64, Kirby's physical appearance does not change unless he uses the move.