If Gust targets a unit with 3 or less might, but the opponent reacts by increasing its might above 3, does Gust still return the unit?

Ruling: Gust does not return the unit. Spells and abilities double-check target legality on resolution, and if the target is no longer legal (might increased above 3), the spell resolves without effect.

Sequence:

• Gust targets a unit with 3 or less might
• Opponent reacts to increase the unit's might above 3
• Reaction resolves
• Gust resolves and checks target legality
• Target is no longer legal (might is now above 3)
• Gust resolves without returning anything

Nuances:

• The spell does not get to change its target to something else when the original target becomes illegal