If you're farming Bounties in Destiny 2 to complete your Season Pass as quickly as possible, you've probably come across the Tidal Lock Bounty. It requires the following: 

Rapidly defeat enemies with precision damage on the Moon (0/7).

What this suggests is to quickly kill enemies using head-shots. However, doing this on the Moon, multiple times, doesn't actually do anything. That's because it actually requires a Nightmare Haunt. Simply take part in one of these, and you'll complete the Bounty almost instantly against the first few waves of enemies. Here's a video of how it's done below.