According to the rule according to which a name in plural which ends in "-ie" ends in "-y" in singular, the name of this Teletubby should be "SwagTubby" and not "SwagTubbie". It's probably a mistake made by SuperMarioGlitchy4, who always writes "Tubbie" instead of "Tubby" in singular.
This character is dead with the others when Mario throws the cartridge of the game into the Sun. In other words, SwagTubbie is lost forever. Despite this, she has made a few more appearances after this.
If one looks closely, SwagTubbie has a Ferrari 360 Spider.