Spectral evolution of AT 2018bwo (coloured lines) as compared to V838 Mon (Smith et al. 2016) and M101 OT2015-1 (Blagorodnova et al. 2017) (gray lines). The main emission and absorption lines have been identified in the plot. The regions with strong molecular TiO absorption have been shown with light blue rectangles. Regions with strong telluric absorption are marked with the ⊕ sign. In these spectra, the [Ca II] is detected in absorption, in contrast with the usual emission profile identified in other transients such as LBVs or ILRTs.