Stone

Stone
	; Various Stone transformations in Melee.
User	Kirby
Universe	Kirby
Article on WiKirby	Stone

Stone (ストーン Sutōn), previously called Rock Shield in Super Smash Bros., is Kirby's down special move. Kirby transforms into a rock, becoming impervious to damage and knockback for a short time. Kirby can still be taken out of Stone form by grabs or grab-type moves such as Yoshi's Egg Lay or Lucario's Force Palm. To leave the transformation early, the player can press the B button while in rock form to return to normal, or wait approximately for 3 seconds after transforming.

Offensively, Kirby can deal damage by using the move in mid air and falling on opponents. When this is done, Stone does excellent knockback, making it useful for avoiding juggling. Due to the sheer weight of Kirby in this form, he will slide off sloped surfaces. In the first two games, Stone does no damage at all if used on ground. In Super Smash Bros. Brawl, however, the attack produces somewhat unnoticeable hitboxes on Kirby's sides, dealing 14% damage with horizontal knockback. Otherwise, the attacks deal 18% damage (20% in Smash 64).

In Super Smash Bros., Kirby can only transform into one type of stone. In Super Smash Bros. Melee and Brawl, however, Kirby will randomly transform into one of the following objects, all having the same properties:

The stone that Kirby normally turned into in his games
A spiked ball
A 100 ton weight, similar to his 8 ton one from Kirby Super Star
A garbage block from Panel de Pon
A Thwomp from Super Mario 64. In Super Smash Bros. 4, the Thwomp now has their look from New Super Mario Bros. Wii.

In Brawl, the move is more powerful than Melee, and it pushes characters away, even if used from the ground. However, if Kirby is hit with an attack that causes at least 30% damage, he will receive full knockback from it, but no damage.

Origin

The move is one of Kirby's copy abilities from Kirby's Adventure, behaving in much the same way. Kirby Super Star introduced the detail of randomizing the transformations to various other types of objects, including a rarely seen golden statue of Mario or Samus. This game also introduced the mechanic of Kirby sliding across slopes while in this form. However, while Kirby could transform indefinitely in his games, he can only transform for a certain time in the Smash Bros. games.

Description from the Melee Instruction Booklet

Transform into heavy objects and become invulnerable for a brief period.

Description from the Brawl Instruction Booklet

Transform into a heavy, invulnerable object. Press the B Button (or absorb enough attacks) to return to normal.

Trivia

In Brawl, it can be seen in Boss Battles Mode and SSE that Kirby never automatically turns back into his normal form while being in his Stone form in midair, or at least for a very long time. However, this has no practical use in normal play.
There is a glitch associated with this attack on the PictoChat stage, widely known as the Earthquake glitch. If the players goes to the edge on the right-hand side and uses the Stone move, Kirby will create shockwaves that cause massive damage (this does not work on the left side, as Kirby will slide off the platform). This will also work on a similar platform made on Stage Builder.
If Captain Falcon's Final Smash, Blue Falcon is used on Kirby in Stone form, it will not work.