Initially named "Tusk" as it was the first form that Johnny sees, Tusk ACT1 is the Stand's base form. It is referred to as the guardian of the Left Arm of the Saint's Corpse.

ACT1 resembles a small, neotenous animal. 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.

It was designed with an axolotl in mind.
--jojowiki.com