tysmftpmg

"Thank you so much for to playing my game."

This is a reference to a voiceline in Super Mario 64, and is an extension of "tysm".
This expression is used mainly within messaging applications after gameplay sessions with friends, similarly or alongside things such as "gg" or "wp". It has a friendly and somewhat humorous connotation, due to the referential nature and grammar of the phrase itself.

Person 1 : "those were some fun games man we'll talk later"

Person 2: "alr gg tysmftpmg"