These mutated crabs can create devastating seismic waves in a form of molten fissures.

--DATABANK--
Basalt crabs that continuously ingested Burntilus stone gradually mutates to this "greater" variant over the decades. For that, it is only found in the cavern area of Inferno Meadow.

While the Greater Basalt Crab seems to be a different animal, it's pretty much the exact same species as it' smaller cousins, since it's eggs still hatches into regular Basalt Crabs.

Initially they don't have any different behavior, still humble and scavenging, just a lot larger, has bigger claws charged with magma capable of forming fire.

It will, however, act as a protector for it's smaller cousins - Should a Basalt Crab got in danger, all Greater Basalt Crabs would come to it's aid. It can strike the ground with it's claw, creating a wave of cracks that bursts into
flames and shockwave. Everything native to Inferno Meadow is immune to this fire shock, and those cracks doesn't damage the ground, either, and would disappears after time passes.

Assessment: If you planned to grab a regular crab, make sure these guys are nowhere near