Well the basic idea could be compared to something like say.. an Enderman of Minecraft, or the Slenderman creepypasta, but the main idea is actually this boss here from the MMO Vindictus(there is some fps issues, but its due to the game update creating alot of lag). It should still give the idea of what it would be like. www.youtube.com/watch?v=pxuOmF… You can also find a better example of it here with the trailer for the boss youtu.be/ipYz1vOPRqc?t=42s As you can see, its a giant, multi-jointed humanoid/bug type monster, that when standing up is incredibly tall, but it also crawls along the ground and bends itself around like a contortionist. It is also shown to have insect wings, but I believe those to be unnecessary for a grimm based on it.The idea I have is more or less similar to it, a tall humanoid contortionist-like armored grimm, that would disguise itself in desolate forests by standing up tall very still, appearing like a decayed tree, until a victim walked past for it to pounce on. Using sharp claws, horns, and protrusions along its exoskeleton-like armor, it launches itself into enemies to do damage