Mayhem Runs are the repeatable heart of the Mayhem Collection, the Joker and Harley Quinn expansion for LEGO Batman: Legacy of the Dark Knight. Each one drops the pair into a locked-down slice of Gotham City on a timer, hands them a primary objective, and scores everything they smash on the way out. One version of the run tasks you with building five firework stands, and completing it leads straight into the DLC’s ending.
Quick answer: Build all five firework stands, then escape through the sewer manhole back in the starting street. Clearing the primary objective is what leads into the Villy Awards ending at the Monarch Theatre.
Mayhem Run requirements: how to unlock and start one
Mayhem Runs are gated behind the DLC’s story mission. Harley Quinn breaks the Joker out of his Arkham Asylum cell, the two fight their way through the rec room and the yard, and they free Poison Ivy along the way. Ivy tears open the asylum with a wall of vines, which is how the pair reach the roof and rocket out to Gotham City.
From there you set up the funhouse hideout on Amusement Mile, where the Joker builds a central planning table. That table is the launch point for every Mayhem Run, and it also sets your spawn location in the city. The hideout is also where Joker-Mite sets up shop for gear and upgrades, and where Hench Master agrees to train inmates for your crew.
The Mayhem Collection is included with the Deluxe Edition on PlayStation 5, Xbox Series X|S, PC and Nintendo Switch 2. Standard Edition owners need the Deluxe Edition Upgrade, priced at $24.99 / £21.99 / €24.99, which also covers the earlier Legacy Collection packs. Platform details are listed on the official game site.
Buy the Glider first: 10,000 studs
The firework run spawns Joker and Harley on a rainy street near Ace Chemicals, with a Joker-Mite purchase station a few steps away. The upgrade you want there is the Glider, which lets you stay airborne after a drop or a grapple launch. It costs 10,000 studs, and without it the rooftop half of the map is effectively closed to you.
If you are short on funds at the start, the fastest top-up is the cart parked near the spawn. Smashing its cash register showers out enough studs to cover the purchase immediately, and registers count as their own scored crime later.
The safe inside the blue shipping container across the water is the single biggest early payout. Pry the doors open with Harley, then solve the lock mini-game by rotating the lock discs until the green bars line up.
Building all five firework stands
Each stand comes from smashing a marked box and then holding the build prompt. Yellow diamond waypoints point you at the next one, and the counter in the corner ticks up to 5/5. The route climbs steadily, so the ground-level stands come first and the rest are spread across rooftops that only connect if you own the Glider.
- Stand 1: Ground level, from a red box beside the shipping container.
- Stand 2: On the first rooftop, reached by a grapple launch and a glide across floating balloons.
- Stand 3: On the rooftop across the street, from a purple and green box.
- Stand 4: Higher rooftop section, again from a purple and green box.
- Stand 5: Built after the Task Force X boss goes down on the rooftops.
Bring help. The Joker’s Summon Crew ability pulls a group of henchmen in behind you, marked by a green ring, and they hold off the rival grunts that spawn while you are locked into a build animation. Red circles on the ground mark where enemy attacks are about to land, so keep moving between builds.
Task Force X boss fight and Chaos Mode
Amanda Waller’s Task Force X hunts you during every run, and the firework route ends with a rooftop set piece against a giant member of the squad backed by smaller enemies. The roster is drawn from a pool that includes Deathstroke, Killer Croc, Captain Boomerang, Deadshot, King Shark and Polka-Dot Man, and the selection changes between runs, so the fight is not identical every time.
Beating it throws up a TASK FORCE X DEFEATED banner followed by CHAOS MODE UNLOCKED. While Chaos Mode is active, every power-up you own can be used at once, and the Joker trails purple and green as he sprints and glides. It is the window to clean up the last stand and sweep the remaining green boxes across the rooftops.
Side crimes that raise your Mayhem Run score
The fireworks pay the headline bonus, but the scoreboard counts everything else you do along the way. Graffiti walls, cash registers, safes, stolen vehicles and A.R.G.U.S. roadblocks all have their own line items, and you can fold most of them into the route without losing time.
| Line item | Count | Studs |
|---|---|---|
| Fireworks (primary objective) | 5/5 | 12,500 |
| Task Force X defeated | 3 | 3,000 |
| A.R.G.U.S. agents defeated | 4 | 400 |
| Heists completed | 1 | 1,500 |
| Safes cracked | 1 | 1,000 |
| Cash registers smashed | 2 | 1,000 |
| Vehicles stolen | 1 | 1,000 |
| A.R.G.U.S. roadblock | 1 | 1,000 |
| Graffiti | 1 | 500 |
| Smashed with vehicles | 5 | 500 |
| ATMs smashed | 0 | 0 |
| Landmarks destroyed | 0 | 0 |
The vehicle entries are easy to combine. Steal a GCPD car off the street, drive it through an A.R.G.U.S. roadblock, and you bank the theft, the roadblock and the objects you flatten on the way in a single detour. Graffiti walls are optional, but spray-painting one takes seconds and still scores.
Extraction and the A.R.G.U.S. Report
With all five stands built, a short cutscene sends the fireworks up over Gotham and the objective changes to Return to the Hideout. Head back toward the starting street and drop into the sewer manhole there. A brief cinematic shows Joker and Harley sliding down into the pipes, which is your confirmation the run counted rather than timed out.
The A.R.G.U.S. REPORT screen appears next with your total time, every objective you cleared, and the itemized crimes. Getting out without being taken down adds a CLEAN ESCAPE +10% bonus on top. A clean run of this route landed at 9:03 with a total of 156,224 studs, which is a reasonable benchmark to beat.
Mayhem Runs feed two of the DLC’s achievements directly. Absolute Mayhem asks for five completed runs, and Villified is tied to attending the Villy Awards.
The Villy Awards ending at the Monarch Theatre
At the Monarch Theatre, talk show host David Endochrine opens the Villy Awards for a packed audience of Gotham villains. Poison Ivy claims Biggest Impact, Hench Master receives Excellence in Recruitment, and Harley Quinn and the Joker earn Best Partners in Crime before heading to the stage.
The celebration lasts about as long as you would expect. Batman, Robin and Batgirl crash down through the theater ceiling, Robin calls the show over, and Batman delivers the line about crime not paying before the arrests start.
The final scene puts Joker and Harley back in Arkham Asylum, where they cheer themselves up by chanting “Lasagne!” with the other inmates. Credits aside, nothing about the run loop changes afterward, so the planning table in the hideout remains available for more Mayhem Runs, reroll objectives, and the rest of the Joker-Mite shop’s equipment.
