Beauty Beard appears in "The Party's Over, Isla de Señorita" when Ice King returns home and takes a shower, questioning his actions. It is most likely some kind of hair product such as shampoo or conditioner. Ice King keeps it next to his razor, neither of which he uses in the episode.
It is a purplish-blue bottle topped with a lighter cap. On the label is "Beaut Beard" (the Y is not visible) with a picture of a white beard under the brand.