How to Keep a Mummy

On the final boss of King's rest, there are two sarcophagi with 2 greenish stones in front of them, simply pull the boss and have 1 party member stand on each stone. Lights will start filling up around the bottom, when they are full it locks in and the right most sarcophagus will being to shake. Simply kill the boss at this point and Miimii is yours! Good luck

This achievement is obtained at King Dazar, the last boss in the instance. Have two players each stay on top of the stones in front of the two sarcophagi, and the lights will start filling up around the stone. Once they are both lit up, the right sarcophagus will start shaking which means that you can kill the boss.

In case you don't get the pet, put down a mailbox and [npc=140125] will be there.

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

so, it sounds like this can't be soloed because of the mechanic of having to stand on multiple stones simultaneously...is that correct?