Can you target units with 5 or more Might with Fox Fire?

Ruling: No, you cannot target units with 5 or more Might with Fox Fire. All targeted units must be valid targets (total Might ≤4) at the time of activation, and you need at least one valid target to play the spell.

Nuances:

• You cannot activate Fox Fire if your opponent controls no units with 4 Might or less
• You cannot mix valid and invalid targets (e.g., a 1 Might unit and a 5 Might unit together)
• All original targets must have a combined total Might of 4 or less when the spell is put on the chain