Use this trigger
call UnitAddAbilityBJ( 'AImo', BaitUnit)
"AImo" just like taunt aura.
Then check every 0.1 second. If Fisher is "Channeling" then skip, else kill Bait.
That's Z fog , not fog of war :|
Environment - Set fog to style Linear, z-start 1000.00, z-end 8000.00, density 0.00 and color (100.00%, 100.00%, 100.00%)