Comparisons of the spectra of SN 2024acyl with the Type IIn SN 1998S and other Type Ibn events (SN 2010al, SN 2019cj, SN 2019uo, SN 2019wep and SN 2023emq) at their very early phases. The inset shows a close-up view of the region between 4400 Å and 5000 Å with prominent flash-ionisation features. The phases marked on the right side of each SN spectrum are with respect to the epoch of their maximum light. Spectra with a low S/N were binned with 20 Å in each bin. The original (unbinned) spectra are displayed in lighter colours behind.