Groundshaker

Overview
The Groundshaker is the largest Sandworm, that is before the inclusion of the Elder Sandworm and Volcano Shaker. The Groundshaker has two attacks, but the one to be feared is when the Sandworm dives into the ground and attempts to swallow a unit from under. This attack can basically reach any corner of the battlefield. The Acid Attack can melt tanks rather easily. Conversely, tank shells are fairly effective.

The 1.5 Patch added new Raider and Critter invader formations, and players will now have to fend off packs of Groundshakers at higher levels. These Sandworms have been made even more threatening with the addition of a third, damage-over-time poison attack. This attack strikes a target and deals splash damage for moderate damage, but the greatest threat comes from the poison damage-over-time effect that lasts 3 turns. Tanks will melt against these Sandworms.

The 2.0 Patch introduced a higher-level version of the Groundshakers that do almost twice as much damage, but with a little less health and armor. Also lacking from these sandworms is their body slam attack, but the increased damage, especially from the poisonous spit attack, more than makes up for this. At the highest levels, players will face formations that include 5 of these (not including the smaller Sandworm Grublings), enough to melt tank formations.

Updates
2.9 Patch
 * Spit attack changed to Indirect.

2.0 Patch
 * Higher level Groundshaker introduced, but lacks "Slap" attack.

1.5 Patch
 * SP/Gold rewards reduced from previous versions.
 * "Spit" attack with poison DoT added.