If multiple effects say that a creature doesnt untap during its controllers next untap step, those effects all apply during one untap step
Sure, it's 12 mana, but if you can somehow discard it you can instead cast it for just 6 thanks to madness
Naru Meha, Master Wizard pairs with it to form a potent and flexible combo that is at its best in wizard tribal decks, though it will fit neatly into any blue deck
When the player uses Thundershock, they can flip a coin
Adeline, Resplendent Cathar is actually most known for its role in the Pioneer Humans archetype since its rotated out of Standard
I'm not sure it's necessary, but it is game warping