See the world before you make it. Genesis puts a live biome map, seed tools and world pre-generation on the Create New World screen, so you can compare seeds and pre-build the terrain before you ever spawn in.
A lone, procedurally-animated spider hunts you across the world... towering over the trees, charging in at breakneck speed... and yes, its THAT spider. The one from the YouTube videos. A mod port of the spider @Cymaera (@TheCymaera/@heledron) created.