So, I was looking through the Skullgirls trading artwork on Steam recently and I noticed that in Valentine's cards, there's an x-ray of Filia's head in the background. See? So this shows that Samson has merged directly with Filia's skull as he is a parasite. However! It's this placement and Filia's biology that realistically would not be possible, even by the game's standards. Now, normally it not too unrealistic in certain positions. As you can see by Filia's offical artwork, Samson is positioned on Filia's head as depicted in the x-ray. However if you look at some of Filia's attacks and some of Samson's expressions, you can begin to see where the biology starts to fail. Let's take a look at one of Samson's expressions where this is most apparent. In this picture, it depicts Samson as laughing with his mouth all the way open. The question is, what exactly is allowing him to move his mouth this far? Or in the game, we can also see that one of Filia's win poses is Samson standing upright and using Filia as a scarf in the wind. Because Filia is facing forward for this taunt and Samson is looking over to the left/right, this means that the top half of her skull has been turned at least 90 degrees to allow this pose to be possible. This can also be seen in some of Filia's attacks. As you can see, in all of these, Filia's skull and biology simply wouldn't allow for them to perform these kind of attacks, no matter how much you would want them to. I really don't want to blame video game logic here, but unless there's a canon reason for why Filia can perform these kind of attacks despite the limitations she and Samson have regarding the shape and limitations of her skull, then I'm not sure what to say. Even Eliza and Squigly, who are also parasite users, have a better explanation regarding how the biology of how their parasites work then Filia ever will.