Treasure event that responds to 'Map' projectile...

The idea here is to prevent the player from accidentally activating the Treasure by randomly coming across the area without having done the necessary precursor of lining the map up with world geometry. 

The final stage of this would be an invisible projectile being fired at an invisible InterpActor that then toggles the particle effect and trigger to on, allowing the player to collect the 'Treasure'. The trigger count is set to 1 to prevent these actions being repeated and upon stepping on the trigger the previously activated particle effect and trigger are disabled.

by 

     Mike Rowntree