I am Pez

....yes

Favorite concept of this is Simon actually gaining the eel's ability (whether because he just has it from the blood, or stole it when he killed it) to mess with people's heads.

In Simon's case, he wouldn't be interested in toying with people, or sending people horrible unfathomable hell visions. However, accidentally giving Grace a horrible vision of what he saw in the Iron Lung? Even worse, dragging Grace into his dream or PTSD vision as a horrified passenger, who can't help, can only watch Simon struggle in the blood and hug him like they're the only people alive after? Yeah

This is completely an accident of course, Simon wouldn't do that shit on purpose, but he wouldn't know how to control his freaky Eldritch bullshit mutations.

No genuinely I love it. Grace is just like "alright so there's a problem. Now we test it and find a solution! Simple!" and Simon's just rolling his eyes fondly and, "great, we're hyper-focus studying my fish demon powers. Fukin' exactly how I wanted to spend my evening." While Grace is mid grabbing a whiteboard, and despite himself Simon feels himself smile because he just adores his stupid goofball of a boyfriend, and it's touching how easily Grace went into wanting to help Simon with an issue.