Unit - Order (Last Created Unit)
Ragnaros
Events
Unit - No unit's life becomes Less than (Percentage life of No unit)
Conditions
Actions
If (All Conditions are True) then do (Then Actions) else do (Else Actions)
If - Conditions
And - All (Conditions) are true
Conditions
(Attacked unit) Equal to Bosses[1]
(Percentage life of Bosses[1]) Less than or equal to 70.00
Then - Actions
Animation - Play Bosses[1]'s cast animation
Wait 1.00 seconds
Unit - Create 3 Lava Spawn (Level 3) for Player 12 (Brown) at (Position of Bosses[1]) facing Default building facing degrees
Wait 1.00 seconds
Animation - Reset Bosses[1]'s animation
Else - Actions
Do Nothing
Use Bosses[1]?
Right after you create the unit put this Trigger - Add Event (Unit - Bosses[1] is attacked) or something like that.