Mad Crab

The  is the first boss you can encounter in the game. It has a sonar which can call Black Bats to attack you. When killed it drops the Mad Crab Sonar (Used in Rare Metals Detector) and Mad Crab Material (Used in Overcharged Plasma Gun). It can swim in water and walk on land.

Location
The  lives in the far west of the Subterranean Lake, near the bottom of the Chasm.

Strategies
The regularly calls for reinforcements (Black Bats). The more turrets the player has built near the boss, the more reinforcements will come. The 's close range attack does some huge damage, but it cannot attack above itself. So one strategy is to build turrets on the roof of the lake so only the bats can damage them.