A person, dog, or cat, who is overweight due to overeating or lack of exercise. Generally, the extra weight will be centered around the middle (or gut), thus creating a rotund appearance.
For humans: I can't find a dress shirt that doesn't look like a tent. It seems like all these dress shirts are really made for Fatty McFattersteins.
For dogs/cats: My cat lives for breakfast and dinner and she has an extra pouch hanging down. What a little Fatty McFatterstein.
A "human" that spends so much time playing video games that their posture is level nerd neck. Everytime anyone goes tryhard they hunch down and their neck gets longer there fore a nerd neck is always hunched down cause they're always going try hard. In other words a nerd neck is a try hard, since their neck is 100% longer than the average human being due to playing too many video games and taking them serious, nerd necks are not even considered human anymore but something more sad. Nerd necks are often found on fortnite, their natural habitat usually being tilted towers.