Spectroscopic sequence of ZTF 18aaqeasu. Phases with respect to r-band peak and instruments used are indicated next to each spectrum. The black lines are binned from the raw spectra shown in gray lines. The magenta line at +18 days indicates the only near-infrared (NIR) spectrum of the source in Y-band from the Multi-Object Spectrometer for Infrared Exploration (MOSFIRE). The data used to create this figure are available.