When I took this picture, I assumed the tube was toothpaste and so couldn't help but enjoy the ironic placement.
I think, instead, it's some kind of dental mold bonding agent which seems to me just as delicious. The black lettering on yellow background reads haga something-or-other (the writing gets lost under the rock.)
It could be hagata （歯形）which means an impression of the teeth, or dental mold; or hagayui（歯痒い）which means to be tantalized or chagrined. Both work equally well for me.