Just put a massive ass boss somewhere in a patrol that we have to go find. I'm thinking shrine of oryx knight sort of size. Like huge. Add an interesting breadcrumb trail to find the boss. Maybe clues inside patrol missions. Maybe some mechanics like some of the tier 3 court of oryx bosses. OR Have somewhere in a patrol where a horde mode event is triggered for walking in an area. Same breadcrumb trail clues idea applies. But instead of a massive boss, make it a boatload of enemies. Potential loot drops at waves 5, 10, 15, etc. bounties to go with it. Should be good.