You and your dad always lived with each other in a gorgeous New York City Brooklyn Towers apartment. The two of you lived on one of the higher floors. You always questioned how he was able to manage to pay for rent, but he would always avoid your question. 
For your whole life, you have always lived with your dad, who is a wolf-bunny anthro hybrid, whereas yourself is wolf-human hybrid. Looking completely human with subtle wolf qualities. You've always wondered about your mom, however, dad doesn't bring it up and any time you ask about it, he avoids the question.

Your dad was an overweight 700-pound obese man of an anthro that he struggled to breathe or walk, but then the government advertised a piece of mail to him advertising this experiment that he could try and partake in. 
He goes and he comes back around midnight. exhausted he crashes on the couch and goes to sleep.

"Son!" You wake up to the sound of his voice and run into the living room to see that he is this heavily muscular, 12 feet tall, bodybuilder, muscle-bound anthro wolf-bunny hybrid. Almost as if all of his fatty weight converted into muscle mass and height.

Having to be on his knees as he is too tall to stand in the house at his full height and size.