Stupefy
Card Text & Abilities
[Reaction] (Play any time, even before spells and abilities resolve.) Give a unit -1 [S] this turn, to a minimum of 1 [S]. Draw 1.
Official Rules FAQ & Clarifications
8 Official FAQsIn the case of Stupefy, Mel, Newly Awakened replaces the event of Stupefy giving -1 [M] with it giving -2 [M] instead. However, a replacement effect that replaces an event modified by the game effect that generated that event will inherit any of those modifications. In this case, Stupefy modifies the “give -1 [M]” game action and thus event with “to a minimum of 1 [M].” The replaced event will inherit the same modification.
Relevant Rules: 375.
Ravenbloom Student’s triggered ability checks whether a spell that you control resolves. You gained control of the Stupefy, and it resolved, so you will have triggered Ravenbloom Student’s ability. Battering Ram and Legion, on the other hand, check whether cards were finalized . Although you gained control of Stupefy, you did not finalize it; you got it after it was already finalized by your opponent. Thus, your opponent’s Legion abilities will be active, and Battering Ram will only receive a [1] Energy discount.
Relevant Rules: 419.4., 419.4.a., 419.4.b.
Swain only checks whether you’ve played a non-token unit, a non-token gear, and a spell. Checks like that do not care whether they were satisfied by multiple cards or a single card relevant to the trigger conditions.
In order for his replacement effect to apply, the event of him being given -[M] must occur. In the case of Stupefy played on a 1 [M] unit, no -[M] is given; it is snapshot to -0 [M]. Thus, there is no suitable event for Gangplank’s replacement effect to replace.
Relevant Rules: 477.3.b.
Although Dragon Form sets the base Might of a unit to 5 [M], it does so via layers. Layers are evaluated when the effect is applied and their evaluation includes all existing applied layer alterations. We process layers in order, starting from the Trait-Altering layer (where this base Might setting effect is applied), proceeding to the Ability-Altering layer (not part of this example), and proceeding to the Arithmetic layer (where Stupefy’s -1 [M] is applied), but this process happens instantaneously; there is no window while evaluating layers for the unit to see itself become 5 [M] and then go down to 4 [M]. As soon as the effect of Dragon Form is applied, the unit is 4 [M].
As a side note, Might is one of the traits that is managed in the Trait-Altering layer, and it is one of the copyable traits that copy effects can replace or add to.
In order to “become 10 or more,” his Might would have to have previously been less than 10. “10 or more” is a state, and Renekton’s triggered ability checks for the event of him achieving that state. If he maintains that state, regardless of how his Might changes, he will not “become” that state.