Niche engineering is considered one of the most important interspecific interactions that shape ecosystems, but this kind of interaction network has not been sufficiently studied so far. Here we present the first observation of grass snake Natrix natrix in the galleries of Cerambyx cerdo. We recorded three grass snake individuals basking and hiding inside the C. cerdo galleries. We suggest the presence of this beetle species may create new environmental niches and improve habitat quality for snakes and other vertebrates.