Sketch showing possible evolutionary paths for RNe (top) and LRNe (bottom). Plausible scenarios for double-peak transients include eruptive phases of the evolution of moderate to high mass stars (with a shell ejection impacting pre-existing CSM), a common envelope ejection in a binary system formed by non-degenerate stars, and eventually (though not necessarily) a merging event with gas outflow interacting with a circumstellar shell. If the primary is an evolved high-mass star, a supergiant (SG) or an hypergiant (HG) with a M_MS >  7−8 M_⊙, or the resulting merger is massive enough, the final outcome may be a core-collapse SN explosion, likely similar to SN 2011ht.