Originally posted by rexpiscator:

one blast from the flying blobs and 'poof' black marble is like straw.

Mmm yeah no. Haven't yet had higher rank variants of gjall attack my base though, but I also likely won't ever have since defeating the boss might disable that event completely. If you must "burrow" to evade gjall from fire-bombing your tarred roof, that's fine, but you could also head outside and fight them off. Barley wine and bows become available in the previous biome.