Coming in a month late
but as others hinted at, you might want to develop a entire ecology.
If this is a fully tidal locked (one face to sun, other to space) you have a most interesting zone around the edges. There might easily be places where adapted photosynthetic organisms could manage. ...it is also a zone where thermal gradient, electrovours might exist. One might also estimate the photosynthetic light energy, IMO (but not calculated) this might go to 10 X over terrestrial 100 watt per meter cubed full sun so even if the productive zone of plant like creatures is only 30 or 40 km wide in the shadow lands it might support life bright side and dark for as far as organisms can go between meals..let me speculate as twice that wide a zone.
Atmosphere matters, a lot, because it tells you if a respiring kind of physiology is possible. Oxygen at 200 C is pretty nasty though. Presuming that night side is not frigid enough to freeze out common atmospheric gases (? Carbon dioxide is the interesting one) you could get some violent storms or if high pressure, fast winds that are not storms. This might also widen the zone where a few animaloids live, wind falls and cooling from a night side flow providing food.
So to start (not at the bottom) there might be a variety of plants and thermocouple sissile organisms concentrated in the day/night line, very tall ones just over the edge into night side, very short ones into the hot side.
Under these conditions, they might have a complex vining form, giant multimeter thick vines connecting the cooler spaces to the hot almost all of them pointing hot to cold, (creating a certain terrain.
The herbivourse, consume the plants, and considering that many of the plants are partially metallic (electrovours, thermo couple metabolisms) they have very strong grinding mouths, with replacable teeth. These beasts might be herd like and have some interesting behaviors, phototrophic skin that turns silvery in the bright light, cameo when in the shade. They also might find a high organic content "suit or ATV morsel" just to taste even if nominally not carnivoures.
-> the little 8 legged squirrly thing, chewed right though my insulating boot in thirty seconds flat. ...
A basic of ecology is that each trophic level gets about 10% of the energy and useful mass from level below it,
so the vines with masses of many tons per plant, can support many eaters of plants, and then at the level of interesting large animals we can have some fairly large plant eaters and eaters of plant eaters.
Now one idea, sort of like, but not the same as dragons and kin, would be organisms that use steam either as a weapon, or as a natural pressure for a projectile weapon. These might organisms that move regularly back and forth between places cold enought to liquify water and the main hot side. (note at much smaller scale, there are some real earth bettles that can fire steam bursts based in a gland that creates Hydrogen peroxiding and catalytic organ)
Another notion would be the fully photovoric mobile organism, I think of interest to play would be how large their reserves are when taken out of the sun. (or the tail out of the shade)
Stariovour
Mass 400 kg, consisting of 7 to 11, tapered tendrils with a central node about 45 cm diameter. The tendrils also have retractable fins and about every 10 cm a pair or three ,several cm long razor sharp hooks.
The stariovour moves by contracting its tendils with some hooks thrust into ground. A large one may have tendrils up to 25 meters long giving it reach for a danger space almost twice that big.
Tendrils are dextrous and strong.
The central body has a very tough hide, as resistant to weapons as a combiantion of reflect and jack and several (generally 2 or 3) sensor tendrils about 5 meters long . It is very sensitive and reactive to shadows.
In its natural environment, (high energy) it can move quickly, a body length of 50 meters in less than 5 seconds. In suitable terrain (well lite but with shadows) it can keep this up indefinitly, if totally in the dark, the reserves are ? ? (less than 10 minutes)
Les
