Seeking Particular monster

[Banshee16]

There was a creature I saw in one of the Monster Manuals, or the Fiend Folio, that was basically a swarm of Fey. It was a species of Fey that I think had a hide mind, and when a bunch of them get together, they can surround an enemy, and cast polymorph on them.

I seem to remember that this is in a WotC book, but I'm not sure which one. Are these an MM4 creature? Or were they somewhere else?

Banshee

 

[Sejs]

There was a creature I saw in one of the Monster Manuals, or the Fiend Folio, that was basically a swarm of Fey. It was a species of Fey that I think had a hide mind, and when a bunch of them get together, they can surround an enemy, and cast polymorph on them.

I seem to remember that this is in a WotC book, but I'm not sure which one. Are these an MM4 creature? Or were they somewhere else?

Banshee

Petals?

 

[Banshee16]

Nope, not Petals. They're like a cloud...the descriptive text said something about them breaking up into pieces because it was the only way to defend themselves, or something like that.

Banshee

 

[boolean]

Possibly the Shimmerling Swarm? (MM3, p. 152)