Isabeau Birindelli, Enrico Valdinoci On the Allen-Cahn equation in the Grushin plane: a monotone entire solution that is not one-dimensional (42K, LaTeX) ABSTRACT. We consider solutions of the Allen-Cahn equation in the whole Grushin plane and we show that if they are monotone in the vertical direction, then they are stable and they satisfy a good energy estimate. However, they are not necessarily one-dimensional, as a counter-example shows.