Feasibility of the Spore Mantis

Question

In the movie, Kong: Skull Island, there is a species called the Spore Mantis.

When stationary, the Spore Mantis looks like a giant, dead log. When active, it looks like a giant insect - a giant, yet slow mantis. As said, the exoskeleton or epidermis resembles wood, however, under this deceptive layer lies a parasitic slug with powerful mandibles. This might suggest two things:

• that the slug itself might help provide extra defensive capabilities, and
• that the exoskeleton is thick enough to be hollowed out without causing any harm or permanent tissue damage.

The name “Spore Mantis” suggests that the species has evolved to reproduce using spores. When stationary, it’ll grow small rootlets from its feet, meaning that its exoskeleton is essentially capable of growing leaves or plants, which also furthers the fact that it’s capable of going through photosynthesis. When not stationary, it can walk around slowly searching for food but since it’s slow, it usually just stays stationary until a creature walks by - like most praying mantises.

Finally, a Spore Mantis is generally placid. In contrast, a provoked one is dangerous in that there will sometimes be other creatures around, atop, or actually living on it.

Could such a species ever feasibly exist?

Answer 1

Yes, but not as you described it

A slug in a mobile exoskeleton isn't exactly what I would call feasible. I mean, technically it's not impossible, except the exoskeleton won't be an exoskeleton because it's alive (thus technically not an exoskeleton) and reproducing with spore is weird. Not to mention that you claim it's capable of photosynthesis, which gives it plantlike features as well. (I mean, fits with the spore, but plants generally aren't bugs.) As described, this isn't a creature which could evolve on Earth, and sounds like something from a different planet.

I've taken the liberty of looking it up and it seems to be that this isn't a slug - it's a giant insect-like creature which is based off the praying mantis. However, it's not a traditional insect and the way insects biology works make them uniquely unsuited for that kind of a size, given that it's built to maximize the utility of the surface are to volume ratio unique to insects, and that those techniques don't work when you shift the ratio to something that a creature the size of a fallen log has. So if I had to pick something to base it off of, I'm going to sea route - I'm thinking alligators.

Alligators share a lot of similarities with this creature, such as the fact that they are generally placid unless provoked (i.e. you've annoyed them or they're hungry), and they enjoy lazing about and looking like logs. Now, granted, gators have four legs, but once we're making adjustments, adding two legs isn't a problem (relatively). Let's say an ancestor to gators decided to skip the whole 'water-dwelling thing' and adapted to land. The species learned to use bark as natural camouflage, mutated an extra pair of leg and there you have it. A creature which is actually capable of living at that size and displays all the behaviors of the 'spore mantis'. (Yes, my version will have a gator head as opposed to the traditionally depicted insect head, but a bit of minor evolution will make it look close enough, and honestly you can't get everything if you want a realistic version of these things.)