> Leaves unanswered the important question: what gender has L'Académie française assigned the French noun for this thing.

I am confident to say it is “Le Blob” due to the “o” in the its name, so it would be male following grammatical gender rules.

The zoo uses "le", which is masculine (but also fwiw is an accepted "default" for genderless or describing a collection made up of individuals of different genders). https://www.parczoologiquedeparis.fr/fr/les-animaux/le-blob-...