So I made a unit with an instantaneous attack and this trigger:
No flaming demons flying around when dummies (Battleships) are shot at...
Coastal Howitzer Target
Events
Unit - A unit Is attacked
Conditions
(Unit-type of (Attacking unit)) Equal to Coastal Howitzer
Actions
Set HowitzerPoint = (Region centered at (Position of (Attacked unit)) with size (900.00, 900.00))
Unit - Add Inferno to (Attacking unit)
Unit - Order (Attacking unit) to Undead Dreadlord - Inferno (Random point in HowitzerPoint)
Unit - Remove Inferno from (Attacking unit)
No flaming demons flying around when dummies (Battleships) are shot at...