False Hydra assistance

so i am trying to run a false hydra in my campaign and one of my players is using detect magic to search the town for whatever seems to be cursing it. I let that player see a strange tint cover the town from the hydras mind song. i cant decide if, when the hyrda comes out to feed if detect magic will work like a faerie fire outline or if they just see some distortions in the general area. if i did make the outline i would probably make them roll a wisdom save after they look away.

i am wondering how other dms would adjudicate the detect magic spell with false hydras

What's a false hydra? Some kind of homebrew? If so, do you have stats for whatever it is?

I assume it's this. In any case, the false hydra isn't invisible, it's using a charm type effect to be unnoticed, and detect magic won't protect against that, though Protection from Evil and Good should either help or render the target immune, and Mind Blank should render the target immune. Really up to the DM though, the false hydra is definitely the type of stuff that would fit nicely in VRGtR (particularly Psychological Horror) so the general advice it has on horror campaigns would likely be useful.

that is the one, thanks for the clarification

it is a homebrew, this is the false hydra i was looking at. the general is that detect magic would not let a player see the hydra because the issue is that they forget it as soon as they see it.

All I know is in order for the false hydra to consume something it has to stop singing so that's why it drags its prey to a secluded spot before it feasts, so I think when it starts to consume something their would be no magic until the singing resumes.

I would also note that the false hydra doesn't really work very well for a quick one-off encounter. It really excels in a slow-burn campaign, as a background thing. The way I'm running it in my campaign is I'm introducing specific elements of it into the storyline early, so as to kind of hint at it's existence. As the campaign progresses, I'm planning on ramping up the distortions caused by the false hydra until my players finally get to confront it. The key to running one is the buildup of tension; quick encounters just don't run long enough for that.

I imagine this would play out much better in the background of another, unrelated issue, Yuniri said. It's the kind of thing where just running the stats in combat don't do it justice. It is built as a mystery that cannot be solved, a distortion that cannot be explained. Also, it would probably work better the less players who actually know about False Hydras.

There's this thread on here, I couldn't find it, but it was about some guy who wanted to do a slow burn mystery campaign, and talked about how his DM ran the False Hydra. I can't remember the specifics, beyond the fact that there was a NPC ranger in their party that they didn't know about and that the hydra ate. They found arrows and wayposts everywhere, but couldn't explain it until they killed the thing, I think. If someone else finds that post, there may be something in there you find valuable.