It's in the nature of a non-subscription MMO that, when freed from the guilt of making the most out of a monthly payment, people will drift in and out of it over time. That's what I've been doing in Guild Wars 2, finding myself falling in love with it for brief periods, before moving on to be obsessed by something else. With the recent Origins of Madness update, I've been dragged back in. It's all down to one of the new world bosses: the Twisted Marionette. Remarkably, it's one of the best encounters ArenaNet have ever created for the game.

My victory over the marionette was a long time coming. It's hard. Not because it requires twitch reflexes, impeccable build orders or the ability to rise above the shame of stupid mistakes. The marionette couches its difficulty in a variety of engaging and starkly different stages that make it not only an enjoyable battle, but also a fascinating social experience.

To understand how well designed it is, you only need to look at the chat window after a failed run. Alongside the inevitable "learn to play, noob" bores, people are occasionally, well... nice.

"Good job, nearly had it."

"Don't worry folks, it's only a game."

"Fail server. How can you wipe on third champ? FFS, Uninstall."

Well, there's always one.

The reason for this almost sickly sweet good will is partly that you're rewarded even if you fail, but also because of the sense of community built over the preceding half hour. The encounter takes place across five lanes, and it's important to keep each one roughly equal. Before the event begins, representatives from each lane will fill the map chat with headcounts and status updates. "Lane 3, 15 people," "L4, 26," "L5 could use some more too," "okay, I'll switch."

It gives us an instant sense of purpose. Almost every other world boss requires little more than turning up to hit the big thing. In fights that do require tactics and thought, those that know what to do often take to patronising those they assume do not. Here, though, the most experienced aren't talking down to the least, but rather marshaling troops and encouraging comrades.

I pick the second lane, and spend a few minutes watching the chat while jump-dodging around my solemn band of fellow fighters. I play a Thief, and so 90% of my effectiveness revolves around being able to act like a hyperactive idiot. It's a role I'm pretty good at.

The countdown ends, the cutscene plays, and we don't fight the boss.

The Marionette fight is great because you never directly attack the Marionette. As much as I enjoy rolling with crowds as they turn up to defeat open-world goliaths, the battles are usually ones of endurance. In the Claw of Jormag encounter, you whittle down a giant health bar while occasionally dodging enemies, shattering ice crystals and dying. When fighting The Shatterer, you whittle down a giant health bar while your character stands completely still and you drink a cup of tea. The Marionette is never directly fought, which means there's no giant health bar to whittle. Instead, the five teams must take it in turns to break the chains that hold it in place.

Most of the encounter is spent in-lane, killing constantly spawning waves of enemies. When the fight starts, players rush off to their self-appointed roles. Some grab hammers, to erect barricades that slow the progress of the invading clockwork monsters. Some jump into metal golems to provide slow firing area-of-effect damage at key enemy hotspots. Everyone else patrols the length of the lane, targeting the Champions that are trying to reach the portal at the top. If they do breach our defence, it charges a bar that, when full, activates the Marionette's energy cannon and kills everyone on the map. This is a thing we would like to avoid.

"Another group has begun fighting around the twisted marionette."

The message goes out to everybody in the event, letting us know that lane one is making an attempt on the first of the boss's five chains. Each lane functions independently of the others, meaning you're never entirely sure of how they're doing beyond these on-screen declarations and the infrequent chat messages. If they succeed, we take a step towards victory. If they don't, the cannon's charge gets a significant increase, and everybody becomes a little more nervous.

"One of the twisted marionette's chains has been severed."

The chat fills with people hastily typing "gj, L1". Their victory sets the tone for the whole encounter. The first warden is relatively easy, so a failure - as well as being detrimental to our survival - is a strong indicator of some serious organisational weakness. Their success doesn't mean we'll win, but it puts everyone in a good mood. Now we pray that lane two doesn't bugger it all up. Wait, that's my lane.

The portal at the top of our lane turns green. We step through and are teleported to the cliff above. Here, we're evenly distributed between five discs, each containing a Power Regulator, each protected by a Warden mini-boss. We have just two minutes to destroy both. After the manic cacophony of explosions below, up here feels more personal. Groups of up to four people are battling simultaneously, both locked in their own struggle and part of something bigger.

Each Warden requires a distinct trick to complete. We're fighting the second: a spinning, hovering, bladed octo-bastard who's invulnerable to damage unless stunned by his own mines (Oh yeah, he lays mines.) Our party of four do well, and we take him out with just over a minute to spare. A further fifteen seconds of gracelessly bashing the power regulator and then... we wait.

All five regulators must be destroyed to break the chain. Three have, but two discs are still fighting their Warden. We can watch but not help, just offer tips in chat and /cheer them on. In previous attempts, I've watched helplessly from the sidelines as groups have wiped out. I've also felt the palpable annoyance from other players as our own group has run out of time without finishing the job. This should be frustrating, but instead it captures something too often missing from MMOs: the sense that it's not all about you. Here, you're not the saviour, and you're certainly not special. You're just waiting, and occasionally dodging the foot of a giant clockwork ladyweapon.

"One of the twisted marionette's chains has been severed."

The final disc finishes with seconds to spare, and we're teleported back to our lane as heroes. If all goes well, we'll not be called upon again. We get back to the chaotic business of defending our portal, and lane three prepare to take their turn. They'll be fighting Warden III, who is a proper bomb-dropping jerk. This is where many a run has come crashing to a standstill.

"One of the twisted marionette's chains has been severed."

Yes! We've got this! Probably. I've never fought the fourth Warden, so I've no idea what his deal is, but surely lane four can deliver.

"One of the twisted marionette's chains has been severed."

They can! We've definitely got this. I mean, yes, admittedly the last time I experienced an uninterrupted run of successes, everything crumbled on the fifth Warden and we lost the event. But that couldn't happen with this group. I've got a good feeling about lane fi-

"An attempt to sever one of the twisted marionette's chains has failed."

Bollocks. Here's where things get a little complicated. It's not that we're in danger of failing - thanks to some effective lane defending, the death-cannon is only a quarter charged - but people have started to move around. When you exit after a chain attempt, you're given a status penalty that stops you entering another portal for a set amount of time. It's designed to prevent zergs of players bouncing between each lane in turn, padding out the number of people fighting each Warden. Even so, you can switch lanes in preparation for when that timer runs out. When lane four succeeded in breaking the fourth chain, the first and second lanes thinned out as people ran to bolster the fifth. Now that the fifth has failed, it's inevitable that the underpopulated first lane will too.

"An attempt to sever one of the twisted marionette's chains has failed."

As one of the few that stayed put in lane two, it's my turn to re-enter the portal. More players run up, reinforcing from lanes three and four. The whole thing's starting to resemble an absurd river crossing puzzle , as everybody tries to work out which lane they can enter to best avert a map-wide electric death-beam.

We teleport onto our respective discs to battle Warden V. It's a pure DPS check: empty its health bar, and it forms new, smaller versions of itself. We need constant stacks of area-of-effect hyperdeath to get the job done.

With thirty seconds left on the clock, four out the five discs have destroyed their power regulators. All eyes are on the last disc. My disc. Twenty-five seconds, and we drain the health of another jumped-up grandfather clock. Luckily, it's the last, and we jump on the regulator. It fizzles out with eight seconds to spare. We win. My first time doing so, and so far my last.

Around one hundred people came into the event as strangers, and around one hundred people left it as strangers. But briefly, for that time in between, we were something more. As a group, as a lane, as a few fighters on a disc, we fought, encouraged, cajoled and celebrated together. More than a solo adventurer in a world of other people, more than a tight-knit raid group of military precision, and more than a huge ball of players listlessly firing at a single boss, the Twisted Marionette picks at an unmined vein of MMO co-operation.

The Twisted Marionette will be live in Guild Wars 2 until February 18th.