First, the Aquatoid needs to be small size. Other than that everything is excellent.
Now for my (least) favorite terror unit, the Tentaculat. This thing isn't even REMOTELY human. Abberation would be very appropriate here. When I see a Lobsterman, I try to sneak away and try to be sneaky about taking him out. With the Tentaculat, there is no sneaking off. Their is no surprising them. You can't out run (or out swim them). You can't hide from them, they WILL find you. It's not a matter of if, it's a matter of when.
Aquatoid Civilian
Time Units 99 35
Health 96 30
Energy 140 65
Reactions 96 30
Strength 100 20
Bravery 110 80
Front Armour 45 0
Left Armour 25 0
Right Armour 25 0
Back Armour 15 0
Under Armour 5 0
Energy Recharge 40 20
Intelligence 8 1
Firing Accuracy 50 30
Throwing Accuracy 50 50
Melee Accuracy 80 50
Look at the bravery. They NEVER panic. Never. "Tentaculats are armed with powerful beaks that can pierce many inches of thick armour, regardless of the material. With their spine-line appendages, a Tentaculat paralyses its victims and bites them to transmute them into mindless things by injecting a fast acting agent. In addition to the mind destroying effects, the Tentaculat's transmutation process accelerates rigor mortis and bloats the victim until it rips through and destroys any suit of armour being worn. The victim will wander mindlessly in a shuffle and try to strangle or strike any X-Com target it comes across with inhuman strength.
Even if one of the zombified victims is killed, somehow, a new Tentaculat bursts from the corpse - unless the killing blow is done with a phosphorous round. This appears to cause the incubating Tentaculat's growth process to fail."
Tentaculat
Damage Type Vulnerability
Armour Piercing 80%
Phosphor 100%
High Explosive 150%
Gauss 90%
Sonic 110%
Freeze (Stun) 110%
Drill 110%
Electric Shock 0%
For High Explosive I would probably go with concussion damage. The only saving grace in fighting a Tentaculat is they can only survive underwater.
Description from game:
Tentaculat
Not even the depths of a Lovecraftian nightmare could spawn such as this indescribable creature. No comparison to any Earth animal exists, the environment that could produce such as this beyond imagination.
Armed with long tentacles the Tentaculat paralyses its victims then transmutes them into mindless things. These progeny can cause death on touch, even through armour.
The Tentaculat is the most fearsome alien yet encountered by X-Com.
http://ufopaedia.org/images/e/eb/Tentaculat.PNG A link to how it looks. That "eye" is not an eye. That's its beak.
Tentaculat Autopsy
The autopsy reveals small cybernetic implants are lodged in the creature's large brain. The vision system is a complex combination of visible light and thermal imaging acquisition. Even in the inky depths of the ocean this monster can navigate with unerring accuracy. There are vestigial organs that seem to be the bare minimum for survival. Each creature has a small stomach with an external connector, it is logical to assume the being is fed by direct nutrient input by its masters.
http://ufopaedia.org/images/c/c3/Tentaculat_Autopsy.PNGThe Tentaculat is most likely Chaotic Evil. Probably the only thing that keeps it from attacking its masters is the masters provide the only way for the Tentaculat to eat.
They are aquatic only.
Organization:
Single (1), Small group (2-3)
For the special ability of the Tentaculat, look at the section of the X-Com D20 containing the Chryssalid.