Choose one or both —
• Deafening Clarion deals 3 damage to each creature.
• Creatures you control gain lifelink until end of turn.
A creature you control that’s dealt lethal damage by Deafening Clarion’s first mode will still be on the battlefield to gain lifelink from the spell’s second mode before that creature dies.
Deafening Clarion’s second mode affects only creatures you control at the time it resolves. Creatures you begin to control later in the turn won’t gain lifelink.