We have already seen creatures, enchantments and one notable planeswalker printed on the opposite side of teased battle cards, including the Marchesa of the niche plane of Fiora or a towering apex predator from Ikoria - the designers said on the stream that theyre digging deep for planar callbacks as well as revisiting recent favourites in March of the Machine
It also doesnt mean any action like an abilities effect, just action cards
It costs , which is steep, but in enchantress you're drawing enough cards to find it and often have enough mana to cast it
The absurd level of potential mana generation has ensured a permanent position for Serras Sanctum in White enchantment-based decks
Once you pay the disturb cost, the spirit soldier transforms into an aura curse
Much like Pitiless Plunderer, if Malcolm, Keen-Eyed Navigator had a once per turn rider on it, we wouldnt be talking about it