Poor little bear, you finally found out didn't you?. But don't worry I can help you get revenge ....
Basically what happened was Goldie found a report of Fredbear being scrapped and with that he found a blueprint of himself which just showed him that he was just a replacement of Fredbear....
And of course Goldie would be upset about that and I think you can tell from the photo what happens next.
Also the purple fur is just a side effect of the whole heart thing
I'm gonna make this an AU at some point
Also Shady won't exist in that AU