Tusk

Tusk is the Stand of Johnny Joestar, featured in Steel Ball Run.

Like Part IV's Echoes, Tusk takes various forms.

Tusk ACT 1
Manga Debut: SBR Chapter 25, Tusk (1)

Ability
Quick-Spin Nails: Tusk ACT 1 grants Johnny's ability to Spin his fingernails at a high speed and shoot them, as projectiles akin to bullets. Once Johnny shoots a fingernail, they take a short time to grow back.

Development
It appears that Johnny is granted his Stand by the marriage between the power of the Corpse's Left Arm, found in the desert, and Gyro Zeppeli's elementary tutelage in the way of the Spin.

Appearance
ACT 1 resembles a small, neotenous animal. It was designed with an axolotl in mind. Its head is of equal or slightly greater size than its body, and it floats with two short, vague, and inarticulate arms and one such leg. Its posterior is marked somewhat irregularly by small stars, behind which dark circles radiate to their points; while four tendrils droop from the base of its trunk to the approximate length of its leg, bearing heart shapes.

On its head, it bears two long, mammalian ears; small, reflective black eyes, under a brow of a troubled angle; a large star at the top of its forehead, behind which a dark circle radiates to its points, and from the center of which a string links with the tip of a cone fastened to the region of its nose. Eight wavering vestiges emanate from its head laterally: Two above; four from its sides, the lower of which, at its cheeks, are also surrounded by a dark circle; and one either side of its chin.

Personality
ACT 1 occasionally produces the sound "chumimi~in".

Tusk ACT 2
Manga Debut: SBR Chapter 43, Silent Way (4)

Ability
Ten-Aureal Nails: Once Johnny learns to Spin the fingernails with aureal rotation, thus bringing Tusk to his second form, he can shoot fingernails that are significantly more powerful. The holes these shots produces move: if, for example, he shoots and produces a hole on a table, he can move the hole on the surface of the table and whatever touches the table's surface. However, the hole leaves a track behind it as it moves. The holes will aggressively chase any target designated by Johnny.

When Johnny shoots a fingernail with aureal rotation, the fingernail takes several minutes to grow back; however, Johnny discovers that by munching herbs or drinking tea, he can accelerate the growing process.

Appearance
Mechanically, ACT 2 possesses small, sturdy torso and arms, greater in proportion to its head. From its head hang two barrel-shaped objects. A barrel-like unit the size of its head is suspended at the base of a short, flat spine. Araki added some elements to make it unclear whether it's animal or machine, like a traditional Stand.

Tusk ACT 3
Manga Debut: SBR Chapter 59, A Dream of Gettysburg

Ability
Through the Hole: By shooting himself with a fingernail Spinning with aureal rotation, Johnny is able to suck his body into the infinite "location" in which the spiral spins into its smallest possible point, Anything other than Johnny's body is destroyed by entering through the infinite hole. Johnny is also able to send a part of his body through the hole, moving it away from his body. This way he can shoot fingernails from different directions, by sending his hands or fingers through the holes.

Development
During the fight against the Stand, Civil War, Johnny, in a moment of deep crisis, sees Jesus, who gives him the hint that leads him to discover the third form of Tusk.

Appearance
Although it is distinctly more human in shape, its head is still embedded into its body. ACT 3 bears sharp spikes growing from both the underside of each of the three toes of its triangular feet, and two from small, truncated, disc-shaped hands. On dark, spherical shoulders it bears the large, bold outline of a star; and from its upper lip to the rear of its head runs a tall, blade-like protrusion resembling a Mohawk.

Tusk ACT 4
Manga Debut: SBR Chapter 85, Ball Breaker (3)

Ability
Infinite Rotation: This Super Spin can pierce through multiple universes, and influence gravity. The damage caused by the rotation is also infinite and will not end unless Johnny were to apply another similar rotation moving the other way, resulting in them cancelling each other out.

When hit by one of Johnny's nail bullets, ACT 4 imbues targets with infinite Spinning motion, making them Spin internally. That Spin goes on forever and never leaves the person or their Stand, forcing them to return to the place where they were hit, or its equivalent in each parallel dimension. Tusk can move through both D4C's Love Train and can move through THE WORLD's stopped time to reach its target which makes it acausal (unaffected by space or time). Tusk can seemingly open portals through space and travel through them as was shown in Johnny's battle with Diego Brando from another universe.

The Spin is also transferable between objects, as the Diego Brando from another universe cut his leg off and threw it to Johnny, transferring the infinite rotation to its user. Another example is when Funny Valentine went into a passing car trying to run away from Tusk, the infinite rotation nearly instantly destroyed it, coming back to Valentine.

Development
Johnny unlocks Tusk's fourth and final form after receiving Gyro's fifth lesson. The principle behind the technique derives from the use of the Super Spin, which requires Johnny to allow his horse to run in its "natural state". By doing so, the horse produces rotational energy in the form of the Golden Rectangle and by combining it with Tusk, Johnny is able to release infinite rotational energy. Because Act IV derives from his horse's running power, Johnny is typically only able to use it when on his horse. He can, however, shortcut the process as a last ditch effort, using a Steel Ball to temporarily galvanize his horse's movement.

Appearance
ACT 4 is of humanoid shape and broad or square build; of articulate legs, arms, hands and fingers. Its head is mounted on front of its chest, and from the bottom of its chest hangs to its ankles a vestment comprising strings of vertical ellipses. like Johnny, it wears a horseshoe on its forehead. The inside of its curtain-like body is hollow, and its face can move around like the Zaku's mono-eye.

Personality
Occasionally vocalizing ACT 1's "chumimi~in", ACT 4 punches while making or inciting Johnny's expression of the Kujo family's "ORA ORA ORA" Stand Cry.

Trivia

 * Johnny can use his Spinning nails to grate cheese, wind spaghetti, and brush his teeth as though with an electric toothbrush.
 * According to himself and Hot Pants, Johnny only possesses Tusk when he carries a Corpse Part; however, he is able to use Tusk even when the Corpse is fully reassembled
 * On occasions, Tusk's name is written with the kanji "爪", rather than it's traditional "牙", which is a reference to Tusk's fingernail shooting ability.
 * Araki specifically created Tusk ACT 1 with being a mascot to Part 7 in mind.