To add the ability:
-
Custom script: call UnitAddAbility(Unit, 'Aloc')
This will add the locust ability to a unit.
"Unit" should be the unit you want to give locust (e.g.: if you set that unit to a variable called "LocUnit", it should be "call UnitAddAbility(udg_LocUnit, 'Aloc')").
Unfortunately, the function "call UnitRemoveAbility" doesn't work for locust.
So in that case, I recommend you to re-create the unit completely (remove the locusted unit and create a completely similar unit at the exact location, with the exact stats etc).
Hold on, I'll create a function for that (the unit's a hero, right?)