I will discuss the impact of tiny self-interactions in models in which the dark matter consists of ultra-light axions (sometimes called “fuzzy dark matter”.) In such models, the De Broglie wavelength - which is of kilo-parsec order - may help alleviate possible problems with CDM on small scales (i.e. the missing satellite, cuspy-halo, and too-big-to- fail problems) while preserving its successes on large scales. However, recent work (e.g. Irsic+ 2017) claims tight constraints on fuzzy dark matter from the Lyman-alpha forest. I will argue that self-interactions (neglected in the Lyman-alpha forest studies) may have a significant impact on the properties of the cosmic web responsible for the Lyman-alpha absorption features.