Help me build a Boggart

[ZSutherland]

Both I and the majority of my players have read the Harry Potter books, and several of them (having taken turns DMing) are very familiar with the monsters in the MM. I want to toss a creature at them, who's stat block they're not familiar with, but that will be familiar to them, OOC. As such, I want to use the boggart idea from Harry Potter.

For the uninitiated, in the novels, the boggart is a nasty household pest who hides in closests, under beds, or any other dark place. No one knows what they actually look like because as soon as they come into someone's view, they take on the appearance of whatever the viewer most fears and can, consequently become quite deadly. This struck me as being a good deal like the Phantasmal killer spell, and so got me thinking, but I have no idea how to adjust the CR for the affect. I know Nymphs have a CR 6 or 7 and can kill just for looking. The boggart would have to successfully touch attack and you'd get both saves, but the Nymph is good, I think. Do they take into account the ability to parley with her or her lack of inherent aggression? Also, since she does that only when she wants to and this creature will do so all the time, how many hit dice should it have to make it an appropriate challenge.

Basically, I've never built a monster of my own before, and am turning to the experts to help with this?

Z

 

[demiurge1138]

The lowest level death effect is phantasmal killer, a fourth level spell. This suggests to me that the boggart's CR could be quite low without too much concern; between 4-7 would probably be best.

And also, why the touch attack if the boggart becomes fearful merely by being seen? It sounds more like a gaze to me.

Demiurge out.

 

[ZSutherland]

Regarding the touch attack, I mostly wanted it for flavor. The spell description of phantasmal killer says that the phantasm touches the victim. They then make a Will save to disbelieve because they have interacted with it, and failing that make a Fort save for partial or die. I want the boggart to be the spell incarnate, as such, the phantasm is confined to his appearance, so he must deliver a touch attack.

Does that signifigantly weaken it?

Z