PolygonCollider2D.CreatePrimitive

public void CreatePrimitive(int sides, Vector2 scale = Vector2.one, Vector2 offset = Vector2.zero);

Parameters

sides		The number of sides in the polygon. This must be greater than two.
scale		The X/Y scale of the polygon. These must be greater than zero.
offset		The X/Y offset of the polygon.

Creates as regular primitive polygon with the specified number of sides.