I think this is a new feature that the June post hinted at.

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Not sure what it is yet, but from what I've done so far, if you bribe with food it clears 5% (regardless of carcass size, so small meat chunks are good) and asking your pride clears 10%. I haven't tried clearing it myself yet, but I think that might also be 5% and use some energy.

You can do it once per hour, though asking your pride might be once per day. I'll see after an hour has passed!

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I was able to clear a part while at 0% energy

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I guessed wrong then x)

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If you do it yourself, you'll get 5% done and you can use your pride right after that to gain additional 10%. Doesn't matter how many lions you have or zow much energy your king has ^^
Let's see what this is... I hope it's gonna be something nice to cool off this grind the event currently has.

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Using the Ushabti also has a shorter cooldown than doing it yourself

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How much is the cooldown from the Ushabti? Doing it yourself has a 2 hour cooldown, I think.

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1 hr, I tried it twice on my side

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I chose to bribe the Ushabti using a gerbil carcass. I got this message:

"You offer food to the Ushabti, explaining that you will provide the god's vessel with food if they'll help you clear the rubble. They happily agree and get right to work clearing the rubble. They sure are efficient little buggers. 5% of the rubble has been cleared!"

Once the page reloaded, the option to clear any rubble myself disappeared and had message "You can clear more rubble in 59 minutes!" I still had the option to ask my pride to help.

Once I asked my pride to help, I got this message:

"With the impending doom, your pride is more than happy to help clear the rubble. They work hard and you get more done with many paws helping. Time for a group cat nap. 10% of the rubble has been cleared!"

Once the page reloaded, the option to have the pride help clear rubble disappeared and I got the message: "Your pride can help clear more rubble tomorrow."

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Looks like the ushabti will remove 5% of the rubble per use regardless of the food item

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This account I changed the order of the options I chose.

I chose to clear the rubble myself first. I got this message:

"You go to work removing the rubble. It's hard work and you'll need to rest for a while before removing more. 5% of the rubble has been cleared!"

Once the page reloaded, the option to bribe the Ushabti disappeared and I got this message: "You can clear more rubble in 1 hour and 59 minutes!"

So by clearing rubble myself, it looks like 2 hours before I can come back to clear more. On my other account, I chose to bribe the Ushabti which is only 1 hour before I can return. Seems like a fairly even trade out. Do it myself cost nothing, but it's a 2 hour wait. Hand over a tiny piece of meat(gerbil, small meat chunk, etc) and I can come back in 1 hour instead of 2.

I asked my pride to help afterwards and got the same message I posted previously. Looks like the pride gets to help once a day regardless of your choice on the other options.

TL;DR
Bribe the Ushabti with meat(sacrifice food) - come back in 1 hour, 5% rubble cleared
Clear the rubble yourself(no energy use, no bribe, etc) - come back in 2 hours, 5% rubble cleared
Have the pride help(no energy use, no bribe, etc) - once a day, 10% rubble cleared

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