Natural Feature → Lair → hive
Creature responsible: Monster → Unusual → gull/waterbird + multiple heads/headless
Visibility: partly covered/overgrown/hidden
Made with Ruby and Roda
For the curious, the source code is available on github.
Random tables from The Perilous Wilds by Lampblack & Brimstone
Adventure Generator based on "Random Sword & Sorcery Adventure Generator" by Ben Ball