If a 3 might creature is targeted by 4 of 6 Icathian Rain darts and the opponent responds with Zhonya's Hourglass, what happens and why?

Ruling: The unit dies twice during the resolution of the four darts. After the second dart deals lethal damage, the unit dies but Zhonya's Hourglass replaces that death (resetting damage to 0). The remaining two darts still hit the same unit, dealing lethal damage again, causing it to die a second time.

Sequence:

• First dart deals 2 damage (2 damage on unit)
• Second dart deals 2 damage (4 total damage, lethal to 3 might unit)
• Cleanup occurs, lethal damage is checked, unit dies
• Death is replaced by Zhonya's Hourglass, unit returns with 0 damage
• Third dart deals 2 damage to the same unit (still valid target)
• Fourth dart deals 2 damage (4 total damage, lethal again)
• Cleanup occurs, unit dies

Nuances:

• Each Icathian Rain dart is an individual ability on the chain, not part of the spell's resolution
• The Icathian Rain spell itself has already resolved when the darts are created
• Cleanup (including lethal damage checks) happens after each dart resolves
• The unit remains the original valid target for all darts even after Zhonya's Hourglass replaces its death