I want to say this started with the April patch but not entirely sure. There will occasionally be a floating bag - the small pouch you normally see when you drop something on the ground - centered on a mob for a few seconds. If I had to guess, it is the spell particle effect for -- well I don't know what -- that is showing as a bag instead of whatever glittery sparkles it is supposed to be. I don't think it is a beastlord spell though since I only see it in raids (I play a BL). It exists, sorry I can't pinpoint it though.
It seems to be a placeholder for certain things. Shaman splash always drops them. I think it was the April update too, was that 2 patches ago? Anyway, 2 patches ago I think.
Indeed, my gnome mage is still finging a pouch (of gnome poo?) at his opponent, when casting Meteoric Bolt!
I always try to pick them up hoping that someone dropped something really cool, like a stack of stat food or something else.
I still see this now using the Adamantite Bo Stick. Not sure if this was fixed for other spells. Leaving the Blued-Two Handed Hammer where it is. They have a weird habit of disappearing from inventory.
I use a velium infused battle staff and I get this also, also with a velium enhanced, raid, battle staff.
All rains cause it, even ones from mobs. I presume you have a shaman healer? Swell produces one as well. The proc itself from the weapons noted isn't a rain or placeholder type spell.
Nope, merc healer. Only one account here. Hmmm, I have grouped with a druid recently and she uses rain type spells.