In the X-Com Universe, this is easily the strongest and most deadly alien footsoldier ever devised, the Lobster Man is a crustacean sapient whose incredible resistance to ranged weaponry earns it the role of "Army of One". It also exceeds in combat ability because it is able to use melee attacks while handling cumbersome weaponry, like the Sonic Cannon or Disruptor Pulse Launcher.
Lobster Men, taller than a man and boasting incredible strength, form the core of the alien army in the Second Alien War. They have an impossibly hard carapace that is hard enough to shrug off any sort of ranged attack save for the Sonic Cannon or Thermal-Shok Bomb. They have four clawed arms, the smaller pair handles weapons and the bigger pair delivers brutal melee attacks. They have titanium-like skeletal systems and eye shielding made from Aqua Plastic. They only have four weaknesses. The first is that their armor is vulnerable to melee weapons, like the Vibro Blade. One or two hits from a Vibro Blade alone can kill them. Second, they also weak against freeze(stun) attacks, so themal tasers and Thermal-Shok Bombs will K.O. them instantly. Third, their armor is weakest on their underside(compared to the other points on their bodies). A Sonic Pulser grenade thrown at their feet can possibly deal some ample damage. Lastly, they are weak against Molecular Control due to their nigh-unrivalled physical strength. An Aquanaut with high M.C. strength will have no trouble jamming or taking control of a Lobster Man's M.C. Implant.
They are often assisted by Bio-Drones during Terror Missions (not that they need them).
"This is a staggering creature, taller than a man and boasting six limbs, it resembles nothing more than an aquatic Demon. The similarities between this creature and the Earth lobster have earned it the nickname of Lobsterman with the X-Com troops.
This is a behemoth of the deep. A carefully designed fighting creature of incredible strength and practically invulnerable to missile fire. Its pincers alone can crush steel."
"Once past its virtually indestructible shell the creature is an amazing construction. Powerful muscles ripple around a titanium skeleton, a sophisticated targeting system with multi-band scanning ability is hooked directly into the creature's brain. It's multiple eyes are protected by harder than steel plastics and it is clear that when well deployed by their masters these creatures are all but unstoppable.
Buried deep in its body are devices of unknown construction and function."