Sans CANT be put into it. It would be major copyright. Nintendo didn't make Undertale. Toby Fox did. And any game that costs money and has undertale characters in it, was copyrighted. Except for, of course undertale itself. So to add sans nintendo would have to make smash free, and yeeeeaaaaahh. Like they're EVER going to do that. Nintendo wants money. Sans + Super Smash Bros = No profit