Reza, Speed Demon

Haste, first strike, vigilance
Whenever Reza attacks alone, put a speed counter on it.
Spells and Abilities your opponents control that target
Reza, Speed Demon cost {x} more to cast and activate,
where X is equal to the number of speed counters on it.
At the end of your first combat phase, you may pay {x}, where x is equal to the number of speed counters
on Reza. If you do, there are an additional X combat
phases after this one. If Reza becomes the target of a
spell or an ability an opponent