#this answer assumes a Kishar necrosurgeon's perspective

[ri47]

I've always thought of pygmalions as looking like mecha sized flood infection forms, what do they actually tend to look like?

A pygmalion can vary in shape a good bit, being a fleshcrafted construct, although you can group most into three categories. These aren't comprehensive, because there are already a few that fall outside of these categories, but they are generally the ones you see

Loose Gore Configuration - Kinda self-explanatory, but that's more or less what you're thinking of here. These tend to be the result of pygmalions made from clonestock made specifically to be fodder for lesser pygmalions (ie jackals and thralls) or other sources where the component souls don't really have a strong (or any) developed sense of self. A pygmalion's form is defined in part by the plurality of its internal contradictions and substantiations, so the form tends to be less coherent when the totality of its being is a resounding ambivalence to the world. These ones are usually encased in armour that gives them a shape. Additionally, those considerations often including a cage for the non-vessel pilot, to buy them time for rescue in the event the pygmalion turns and attempts to rip them out. Loose Gore pygmalions can in many cases be identical to other constructs, such as necromatrices, because Ayin/Azoth/Divine Flesh that isn't given shape will default towards a purpose-fulfilling shifting mass of gore

Borovit Configuration - This is the form of the vast majority of true pygmalions and the one that is most immediately recognisable as a mecha. They trend towards looking humanoid, but usually show signs of insectoid anatomy. Borovit configuration pygmalions come in a range of body types and forms, not to mention various sizes, but most could, for example, pick up and utilise a sword designed to-scale with them. It's worth mentioning that some lesser pygmalions land on a gradient between Borovit and Loose Gore, but for a pygmalion to qualify as the former, they need to maintain a consistent physical form with an internal configuration (what exactly is inside can vary, be it pseudo-organs, bones, muscles, or what have you) that is capable of regenerating to its original form provided there is sufficient ferrous humor.

Velnias Configuration - Velnias pygmalions resemble enormous non-human animals, yet still maintain the sort of anatomical structures you would expect to see on a Borovit pygmalion. They tend towards looking like avians and reptiles, but it's not uncommon to see one that leans more towards arthropod features. More rare, but not unheard-of, are Velnias pygmalions with aquatic or mammalian forms. Unlike Borovit, Velnias configurations sometimes manifest in lesser pygmalions with no element of ambiguity towards Loose Gore. What exactly leads to a Velnias pygmalion is unclear, with some theories being that they're the result of strong emotions in sacrificed souls without articulate beliefs, but that's not exactly substantiated in any meaningful way. Velnias pygmalions seemingly cannot be made on purpose.