(For example, another effect might cause that ability to trigger an additional time.) In such a case, even if you pay mana as the triggered ability resolves, this permanent won't transform because it already transformed while the triggered ability was on the stack
Instant Color tag templates(None) Harmonic Prodigy Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.) If a triggered ability of a Shaman or another Wizard you control triggers, that ability triggers an additional time
Personally, I thought that it had one more evolution left, like the Ancient Gear Fusiondog, with an effect to counter Link Monsters, so it was a pity that it ended like this
Twilight Masquerade brings new Items, Supporters, Pokmon Tools and Stadiums
The forces of light and darkness intertwine, OPENING THE GATES OF CHAOS