The Pet Simulator 99 Summit Rubble Wall is the extra barrier at Diamond Summit in Update 99. Send your strongest pet stacks against it to unlock the Rubble Egg, which contains five new pets, including Crackling Agony.
BIG Games added the wall on 24 October 2026, a week after Diamond Mountain opened. It’s the toughest obstacle on the mountain, although its difficulty drops as the event week progresses. This challenge belongs to Diamond Mountain, not the separate PSX Classic portal.
Where Is the Pet Simulator 99 Summit Rubble Wall?
Make your way through the camps towards Diamond Summit, clearing each earlier Rubble Wall along the route. The new wall is waiting at the top. Don’t confuse it with the barriers you already broke during Update 98: getting to the summit and breaking this new wall are separate steps.
Our Diamond Mountain walkthrough explains the original climbing route, camp walls, mountain boosts and summit activities. Use it if you have not unlocked the top of the mountain yet.
How to Break the New Wall
- Climb through Diamond Mountain to Diamond Summit and locate the new wall.
- Assign your strongest pet stacks to the wall. Bigger damage from those pets means faster progress.
- Use your Diamond Mountain upgrades to improve wall damage and stack capacity.
- Keep those pets working until the barrier is destroyed, then move through to the Rubble Egg.
The Pet Simulator 99 Summit Rubble Wall uses the same progression you’ve been building throughout Diamond Mountain. Wall Power increases damage, Wall Slots allows more pet stacks, and Offline Hours keeps your pets working longer while you’re away. The mountain-specific Damage Boost helps against walls as well as the Yeti.
If progress is slow, switch in your strongest pets and spend Acorns on your wall upgrades. You don’t need to hunt for a key: breaking through is the objective.
Does the Pet Simulator 99 Summit Rubble Wall Get Easier?
Yes. The developer says it becomes easier as the week goes on, giving later arrivals a chance to catch up. Keep your strongest stacks assigned and use the wall upgrades you’ve unlocked. BIG Games hasn’t supplied a fixed health figure or a daily reduction schedule.
What Is Inside the Rubble Egg?
The Rubble Egg becomes accessible when the Pet Simulator 99 Summit Rubble Wall is destroyed. There are five new pets inside, described by BIG Games as progressively stronger. Crackling Agony is the strongest of the five.
Trail Luck, one of Diamond Mountain’s upgrades, also works when you hatch this egg. If you have Acorns to spend on Trail Luck, the upgrade is useful for this new egg as well as your earlier trail farming. Unlocking the egg gives you access to its hatches, not an automatic rare pet.
Rubble Egg or Yeti: Which Pet Should You Farm?
The Pet Simulator 99 Summit Rubble Wall opens access to the egg, but several of Update 99’s rare pets are earned elsewhere. Here’s which activity to focus on:
| Pet | Where to find it |
|---|---|
| Crackling Agony | Rubble Egg behind the summit wall |
| Titanic Crackling Agony | Feed and fight the Yeti |
| Huge Expedition Penguin | Feed and fight the Yeti |
| Huge Summit Moose | Mountain Trails chests |
| Huge Ranger Bear | Expeditions |
| Gargantuan Abominable Yeti | Yeti boss |
The Rubble Egg’s Crackling Agony is not the Titanic Crackling Agony, which comes from the Yeti. For those other routes, see our Yeti guide, Secret Trails guide and Expeditions guide.
Why Can’t I See the Rubble Egg?
First check that you have reached Diamond Summit and broken the new wall, not just an earlier camp wall. The Pet Simulator 99 Summit Rubble Wall must be cleared before the egg opens. It is also easy to confuse this with PSX Classic: that portal has its own progression and eggs, and the Rubble Egg belongs to Diamond Mountain in regular Pet Simulator 99.
After breaking the wall, use your saved Trail Luck when hatching the Rubble Egg. Head to the Yeti for Titanic Crackling Agony or Huge Expedition Penguin, and to Trails or Expeditions for their respective Huge pets.
Related Guides
More on the Pet Simulator 99 Summit Rubble Wall, its surrounding mountain activities and other Update 99 mechanics:
Official source: BIG Games, Pet Simulator 99 Update 99: PSX Classic!.
