Invasive species can be bad times pretty much anywhere, but nowhere do they cause so much trouble as an island. In the closed environment of an island, just a couple of out of place animals can utterly transform an entire ecosystem. Invasive brown tree snakes in Guam have devastated populations of native birds
that once dined on the island's spiders. With those birds on the ropes, Guam's spiders have taken the run of the place. The result is an arachnid population boom so serious that gaps in the island's tree canopy are now regularly filled with enormous spiderwebs. For every one spider on neighboring islands not afflicted by tree snakes, Guam now hosts up to 40 of the creepy crawlers
, turning Guam from a tropical island paradise to a snake and spider dominated horror show right out of every Dungeon Master's dreams.