: If a Fiend Tuner exists on your field, or if a Special Summoned monster exists on the opponent's field, you can activate this effect in your or the opponent's Main Phase
When you activate a creatures ability, it goes on the stack, and at that point its independent of whether the creature stays on the battlefield or not
Famously synergizing with Fireball, this combo enabled worryingly consistent kills on as early as turn one in Vintage
This method involves placing your in a standard inner sleeve, which is then inserted into a larger outer sleeve
You can't activate it without a target in order to return Chthonian Nightmare to your hand
Their normal attack, Fabled Flarebolts, require them to discard a fair number of Energies, though at the maximum potential can unleash 270 damage on the Active foe