Flowey: No problem, Ava...

Sans: {Mind: You know what. She's cool, I'll just tell her...} Y-Yeah.... I do.......

Gaster: It's alright. Not many people know what a semblance is anymore anyway. A semblance is basically a, er.... Like a superpower! A superpower that's generated by your SOUL. But, it's different from magic. Because, it generates powers that Magic can't. Except, every semblance has a downside as well. For example, Sans was given emence power, and can do more damage then most people, but he also gets exhausted must faster.... Although, sometimes people who have already unlocked their semblance, can unlock another's. Perhaps me or Sans could unlock yours? Then, your semblance will be based off of your SOUL trait, so it'll be easier to tell.