Pitch Invasion

TLDR;

1. Pick up glowing cola item at the entrance to the first boss next to the adds, you'll get an extra action button.

2. Pull boss.

3. Throw the cola onto Ledley the Bold, he jumps down with some others.

4. Kill Ledley.

5. Kill boss.

Can confirm that if you die after you kill the mobs, you still get the achieve.

Pick up [spell=278524] before the boss and throw it at [npc=142625] after you engage the boss. [npc=142625] will cast [spell=278673] throughout the fight so you should interrupt the spell and kill him and the other adds asap as they will throw grog, making you drunk for 10 seconds.

If you need help with the other achievements, check this TLDR guide for all achievements: [guide=6418]

Just to clarify what rotomthe3rd posted, though his information is largely accurate and helpful, just outside the boss room on the right hand side is some kind of interactable item that gives a single player an extra action button. Use this extra action button to get a ground-targeted reticle and throw it at Ledley, in the stands on the right. I'm unsure if you need to get him hit by the boss' abilities, though I suspect not. In either case you want to be there to pick the adds up.

Ledley himself will try to cast Red Card. We kicked this every time and have no idea what happens if it gets off, but since there's nothing else to kick on this fight you may as well. His adds will each throw grog at a random person every few seconds, doing high damage and making them progressively drunk for 10 seconds.

Just lust when they drop down if you have it, blow them up quick and pop defensives if you're getting picked a lot (pretty sure it caps at 10 stacks). Also make sure you don't ignore bombs from the boss and continue kicking them in, as each bomb that goes without hitting the boss leave a DoT and a damage taken increase on your group.

My btag is FrostyShot#1667 if you have any questions about the metas. (US Servers)