I downloaded Malwarebytes and scanned. Also encrypted. My tablet still has that Dear Google User pop up when I play a certain game
In your question, you did not say which OS your tablet is running. Since depending on whether it is Windows, MacOS or Android, the steps for finding the cause of Dear Google User pop-ups, and then creating a way to remove them, will differ.
However, we can advise you to follow these steps to remove Dear Google User pop-up:
1. open your browser settings
2. open the list of installed extensions, and with great suspicion check each of them, maybe one of them is a virus, delete it
3. close the browser and restart the computer, if the Dear Google User pop-up continue to appear, then try resetting the browser
Instructions on how to reset browser settings, you can find in this list: