Barely bulkier than many a body cap is the newly introduced Laowa 10mm f/4 Cookie lens for mirrorless APS-C cameras. The manual prime lens measures just 2.5cm in length and weighs 130g.
Laowa 10mm f/4
According to VenusLens, its 109.3° angle of view makes it the widest rectilinear imaging "pancake" lens ever. The optical design consists of 12 elements in 8 groups, including 4 ED elements, and the aperture consists of 5 blades. The closest focusing distance is 10cm.
Filters with a 37mm diameter can be used, the optics itself is slightly thicker with Ø 59.8mm. It is apparently available now for Canon RF / Nikon Z / Sony E / Fuji X as well as L-mount, at a price of (plus duties / delivery from Hong Kong).
Laowa 10mm f/4 on the Sony a6100