Dark bubble. Panel (a): LOS magnetogram from SST/CRISP. Panel (b): Ca II K map at −49 km s⁻¹ from SST/CHROMIS. Panel (c): Ca II K profiles normalized to the continuum for the location marked in panel (b) (solid line), and the average over the whole FOV of the observation (dashed line). Panel (d): Time evolution of the normalized Ca II K intensity at −49 km s⁻¹ for the position indicated in panel (b) (orange), and the unsigned magnetic flux from SST/CRISP within the red rectangle (black). An animation of this figure is available online showing the time evolution from 08:07 to 08:59 UT.