Have Construction Robots in endangered areas. Higher 'Walking Speed Modifier' of a tile improves these effects. It severly hinders their attempts at surfacing. Research new Orbital Seismic Scanners tech to be aware of worm movements. Turrets are hardcoded to act this way, so this can't be fixed, unfortunately. Worms won't target non-military structures by themselves. This late-game change shakes up your turtling, making even the best-laid defences vulnerable to attack.

When they find your structures they will surface beneath them, destroying them from below before surfacing to spit acid splashes at nearby military targets. Starting from evolution factor of 75%, Big, Behemoth and Colossal worms gain the ability to dig underground and slowly tunnel towards your base (they are attracted to the highest pollution area). Most importantly: Worms can come for you!

The higher tier worms are bigger, tougher and attack with a long-ranged area-effect acid splash This mod adds extra tier of worms, Colossal. Note: This is an update to 0.15+, all credit goes to iamseph for making this mod.

Download worm big