An elastic-walled Hele-Shaw cell, i.e. the narrow liquid-filled gap between a rigid base plate and an overlying elastic sheet, has been used as a model to study e.g. laccolith formation, lava flow, airway reopening and the viscous-fingering instability. When liquid or gas is injected, the elastic sheet is deflected upwards to form a blister that spreads horizontally outwards. In this talk, I will discuss how the interaction between viscous fluid, elastic solid and possibly inviscid gas in this simple system gives rise to several interesting physical phenomena (including, but not limited to, the ones mentioned in the title). Asymptotic analyses reveal a wide range of different behaviours depending on the relative strengths of viscous, elastic (bending and tension), gravitational and surface-tension forces