Spectral sequence of pseudo-narrowband images of LAB 1 from 4971.5 Å to 4999.0 Å created from the continuum subtracted MUSE datacube. Each image has a band-width of 2.5 Å and in order to enhance low-surface brightness features the images have been smoothed with a σ = 1 px (0.2″) Gaussian kernel. In each panel, we indicate the positions of known galaxies within the blob (see Sect. 2 and Fig. 1). Moreover, we show in each panel a scale that indicates 50 kpc in projection at z = 3.1 (6.49″). The morphological features described in Sect. 5.1 are indicated in the bluest image where they become visible. We also indicate that we trace Lyα emission ±3000 km s⁻¹ around the central sources of LAB 1. North is up and east is to the left.