If I play Challenge targeting my 5 might unit and opponent's 4 might unit, and opponent responds with Shakedown to kill my unit, what happens when Challenge resolves?

Ruling: Shakedown resolves first and kills your unit. When Challenge resolves, it cannot find your unit to deal damage to it or query its Might, so nothing happens.

Sequence:

• Shakedown resolves and your unit dies
• Challenge resolves but cannot find the targeted unit
• Challenge does nothing since it cannot query the missing unit's Might

Nuances:

• You cannot choose a different unit when Challenge resolves because targets are declared when you put the spell on the chain, not on resolution
• Cards with targets require you to declare them upon putting the card on the chain
• Other choices (that are not targets) are made on resolution