I tried to use cyclonic rift (no overload cost) to bounce my opponent's Ugin, the Spirit Dragon back to his hand as soon as he entered the battlefield so he couldn't use his -x ability. The player insisted that I couldn't use my instant before hand because he had priority and I need some sort of trigger. Please tell me I'm right and he's a moron.
Responses (1)
You are totally allowed to play an instant as or after he summons a planewalker. You must state "In reaction to you summoning Ugin, I play..." and then whatever spell you cast goes on 'The Stack'. He can then play another instant 'in reaction' to yours.
However, with planewalkers, (and I'm not 100% sure about this) after they are summoned and then you bounce it back to their hand, I believe they may activate one of the planeswalker's abilities in reaction to your spell. This ability then goes on the stack and resolves first.
But the average instant spell DOES NOT need a trigger. You can play an instant literally any time unless another spell or ability says other wise.