2017-04-18 : A split card only counts once for Cryptic Serpent’s ability, even if it’s both an instant and a sorcery.

2017-04-18 : Cryptic Serpent’s ability can’t reduce its cost to less than {U}{U}.

2017-04-18 : Cryptic Serpent’s ability doesn’t change its mana cost or converted mana cost. It just reduces the cost to cast the spell.