Morph + Cascade (Maelstrom Nexus) interaction
When casting a morph creature with [[Maelstrom Nexus]], it should be treated as a Cascade with MV 0 (which just reveals the cards of your deck and then shuffles). Instead, the Cascade trigger is as if the base creature were cast normally. This also reveals which creature is being morphed, being named/its image shown as the source of the trigger.
Maelstrom Nexus - (Gatherer) (Scryfall) (EDHREC)
{W}{U}{B}{R}{G} Enchantment The first spell you cast each turn has cascade. (When you cast your first spell, exile cards from the top of your library until you exile a nonland card that costs less. You may cast it without paying its mana cost. Put the exiled cards on the bottom of your library in a random order.)