I played Horn of Plenty and discovered Shaladrassil (and reducing it cost by 2). Next turn with Marooned Archmage on board Shaladrassil got to 3 mana. Then I played a 4 mana minion. But when I played Shaladrassil it was not upgraded somehow.
I’m guessing this is because “your first spell each turn costs (2) less” is an effect that applies to you, not directly to the cards in your hand.
To put it another way, imagine you have a handful of spells with Marooned Archmage on the board. All the spells will show with -2 to their mana costs, right? But obviously they aren’t all actually reduced by 2 mana.
The reduction is (mostly) cosmetic. Behind the scenes, the cards still retain their real costs. The mana reduction is not actually applied until you decide to cast one of them.
So, when you played the 4-mana minion, Shaladrassil still had 5 mana cost (even though, yes, it was displayed with a 3 cost).
Doesn’t stand against an actual corrupt card that will get corrupted this way
4 mana ring toss
reduced to 2 by Marooned Archmage
Play a 3 cost minion
Ring toss gets corrupted
https://hsreplay.net/replay/dXFSn4DmN7NGdGi6CefBpS#turn=10a
All your spells actually cost 2 less until you play one, that’s not cosmetic
Shaladrassil itself does not have the Corrupt keyword, so that is a possible explanation why the behavior is different.
I have no idea if it is intentional, or a bug.
both cards read that their outcome change if you play a card that costs more while they are in your hand
Two different sentences that describe the same behavior
Even affected by a temporary cost change, the new cost of a card is its current cost. Cards in your hand are seen as their current stats. Cards you play are seen for such mechanics with their current stats.
If you play a 4 mana minion and it’s not considered of a higher cost than a 3 mana spell, that’s a bug