Glass You Might Drink Out Of When You Fight Sans

• It's a cup with transparent portions. Depending on the contents, Sans's eye and bones will change colors.
• ... if you use any color other than blue, he will turn into an AU. Be careful and drink (blue raspberry lemonade) responsibly.

This official UNDERTALE drinking glass was designed by Ade; it holds about 11.67 fl oz (345 ml). Sans's eye color is determined by the color of the liquid you're drinking.