The Celestial Toymaker appeared in the episode of the same name. He is ronery (literally) and turns people into toys.
In the episode, an actor totally drops the n-bomb, and someone decided it was a good idea to leave that in and broadcast it. Tellingly, "celestial" is old timey >implication talk for "asian".
Some other undignified stuff happens in the episode, too.
It's racist, boring and generally shit but part 4 is one of the most unintentionally hilarious pieces of television ever broadcast. Part 4's also the only episode we have a full copy of so you might as well just watch that and look up the other three on
TARDIS Data Core Wikipedia.