For example, if that spell's mana cost is and you have one experience counter, you could choose 5 as the value of X and pay to cast the spell
The key is to pick your challenges where it works best to ensure that Hydra, Deadly Serpent stays alive long enough to use its nasty ability
When Im thinking about cards that really allow one player to do it all every time they hit the board, this is one of the first that comes to mind
15 Galazeth Prismari The founder of Prismari College of Strixhaven, Galazeth Prismari is a potent Izzet elder dragon capable of synergizing with artifacts, instants, and sorceries
However, theres still counterplay for the opponent, since many decks could respond by casting or discarding cards known to the blue player
The first cards with the advisor creature type were printed in the Portal Three Kingdoms MTG set