If you are wanting to know how to get a black Razzby in the game that only means that you are in the final stages of the game because it is a final challenge for Shelda in Bugsnax and for them you will have to find the entrance to the ruins near the great pyramid to the left of Shelda. That said, it is not entirely easy to enter so in this guide we will say everything you need to do so.
At the entrance that we mentioned at the beginning of the guide (that is to say near the pyramid) on the ground you will see a circle of earth with some boards and stones on it. This is the entrance and you have to break it. To break the floor you will have to put a little hot sauce on it and the Buffalocust that is flying will bombard it in a nosedive, it will break it and you can fall inside.
You should explore the area so that you don't have to worry about forgetting things later. In it there will be a door near where it was dropped with some plants on either side and a small ledge. Exit and look left to see the Black Razzby.
To remove it, toss your Buggy Ball and cover it with chocolate from your Slinger Willow. The Black Razzby loves chocolate and will follow it. Now, you need to carefully lead
it across the room, making sure to avoid the Incherritos. Use the stones on the ground to avoid them.
Guide him to the end, using the ledges for a good vantage point. Don't drop into the room, as this will actually make it that much more uncomfortable.
When you get to the end, take the Black Razzby to the jump platform and this will send it through another hole, and the mission is complete. Now you can go back to Shelda, who will agree to go to Snaxburg. Now that you know how to get a black Razzby in Bugsnax you will be able to accomplish this stage of the game more quickly because you will know how to act in everything. Luck!