Yes, my family name is Gaunt. Yes, I'm a pureblood. Yes, I'm in Slytherin.
Yes, the House of Gaunts was thought to be extinct but nobody really took notice of a small fringe of the family that had exiled themselves to Bavaria and remained hidden and isolated while also trying to preserve the pureness of Salazar Slytherin's ancestral House.
Yes, my parents are brother and sister. I know gross. But perks with it comes that I am a Parselmouth - we have three family snake pets (one's an asshole, the other one is a snob, I only enjoy spending time with the youngest one; an Albino horned bush-viper I call 'Milky'). Downsides? Many. I have bad genes: I'm completely non-athletic and have no stamina whatsoever (I hate Astronomy and all the stairs to its class), i'm easily prone to diseases, and I have a very moody and ever-changing disposition.
My pet is a normal house-dwelling rat that survived from being turned into dinner for our family snakes by putting up a proper fight - really, it was very entertaining to watch! So I decided to reward its courage by making it my personal pet that gets to roam around the Hogwarts corridors with me, nestle in my robe during lunch and sometimes being transfigured into a water goblet.
I don't work well in teams. I don't make for a good best-friend. I get stiff when I have to attend a party. But heck, I can brew the hell out of a potion!