RueOx Pump and Dump refers to the method used.
The owners of the group will buy all of the assest they plan to 'Pump' before telling everyone else.
Once this is completed, they will tell the group of people who join the discord chat to buy the assest they purchased.
Once the price increases, they start selling to people who are now buying because they where told too. 'Dumping' everything they have.
Someone will be left with a worthless assest at the top of the price peak. That's why its a scam.