I really like this crawl!! Your map is really clear, and so’s your type. Bursting with creative ideas here; I presume the spider-folk are indeed spider crabs. I wonder what the crawlers are… but man, “Those who fail […] dissolve into a mass of tile crawlers in 1d6 +1 days.” That does a lot with a little. Kudos! You drop a lot of hints, and it makes me curious how this basin intersects with its wider world…