I guess illusion would probably be the best term for it. I had a swordfight with Ares once and all the mortals thought that we were pointing guns at each other. There are a few mortals who can see right through it, but mostly even demigods have to know what they’re looking at. Which is super helpful when you’re being attacked by monsters, let me tell you. [not.

[Percy opens his mouth and then frowns, clearly horrified by this concept] What? Are you serious? I mean, I get people not being happy, but that’s just stupid.