>>78218962One theory says he's secretly a human in disguise. His obesity is multiple layers of costuming. That's why his teeth never move when he speaks (unlike Papyrus), and that's why
he can bleed from the mouth without his skeletal neck showing any blood.
>>78218714>>78218957He's pretty close to being that smug, yeah.
Just since nobody else is sharing: his guiding personality trait is laziness. He's aligned with the monsters, who are generally trying to hunt down the main character; but for reasons that become clearer later in the game, he just doesn't care much about capturing anybody. All his font is stylized in Comic Sans to show off his laziness. He makes friends with the player pretty quickly, and saves them from a bad situation; but the person he cares about the most is his brother, who wants to capture humans to make friends.
The way Sans acts from there kinda depends on how you treat his brother. Make friends with his brother, or let him catch you enough, and Sans will be totally chill with you, take you out for meals, give you friendly advice, and occasionally spook you out. If you hurt his brother, then he'll become incredibly distant, a little sad, regretful, and near the end, basically says "look, I know this is just a video game and you can reset it, but you should really think more before killing people for no reason other than seeing the bad endings." In both of these situations, he'll still keep a huge smile and make skeleton jokes.
Some people like how quickly he can move between being totally chill with skeleton jokes and suddenly questioning the player - not the character, but the player.
He also has a larger role in the absolute worst ending, where he intentionally exploits the game mechanics in an attempt to frustrate the player too much to go further.
So yeah, pretty much a smug chucklefuck.
