Amulet of Storms, an artifact amulet of flying that additionally grants shock resistance when worn, and allows you to pacify true v monsters (i.e. not alternative forms of other monsters that happen to be turned into a vortex as a defined alternative form, such as vampires and the Wizard of Yendor, but counting shapechangers such as chameleons) when chatting to them.

New monster “vapor cloud”, similar to the fog cloud, except it is made up of potion vapors and instead of doing damage, it causes the uncursed vapor effect of potions to happen to you when engulfed. (There probably has to be something preventing a vapor cloud of paralysis from paralyzing you eternally.)

When it moves over a potion, it consumes the (topmost if there are multiple) potion and changes. With 50% probability, it either switches to the potion consumed, or rolls for alchemy as if combining its existing potion cloud with the new potion (probably rerolling events like turning to water, evaporating, and blowing up in an alchemic blast, though it would be funny if it blew itself up).

Hostile vapor clouds will intentionally seek out harmful potions to consume and will avoid beneficial potions.

Polymorph vortices, a monster which has a passive polymorph attack (i.e. hitting it in melee polymorphs the attacker; hitting it with missiles polymorphs the missiles) and once per turn polymorphs either one random item from its inventory, a monster it has engulfed, or a random item from that monster’s inventory. Player-style magic resistance prevents the effects to a creature or its possessions that would otherwise be affected.

Vortex monsters can occasionally suck you a square in their direction when they’re not next to you, which can of course pull you onto dangerous terrain or a trap.

Balrogs could also do this if wielding a whip, at a closer range.

Blade vortex (v), which is a whirlwind of spinning blades. It has two engulf attacks that deal 2d4 physical damage each, and is difficulty 12. Apart from generating normally, it can be created by polypiling a sufficiently high number of blades at once similar to how golems are created. When killed, it drops an assortment of bladed weapons, mostly smaller ones like knives, daggers, and short swords, and possibly a chain or two. It can be harmed by thrown potions of water, rust traps, and rust attacks.

Another iteration of the proposal is to make its blades its inventory rather than just assumed to be part of the monster, with the following interesting implications:

• Rather than just the monster dealing damage, it actually makes attacks with randomly selected weapons against an engulfee, which could do things like silver damage if the vortex has silver weapons whirling around inside it.
• Could have 6 attacks, each of which must use a different weapon. (If it only has 3 weapons in its inventory, it only gets 3 attacks.)
• It would also have to generate with an inventory of a few blades, selected randomly from the set of bladed weapons under a certain weight (no giant battle-axes).
• If it passes over blades lying on the ground, those are sucked into its inventory (which would make it even more deadly if it attacks with weapons it holds).
• Also, hitting it with thrown blades will result in those blades being sucked in (and possibly dealing no damage since it’s obviously not harmed by its own blades).

Assuming some sort of wind blast is implemented: There is a small percentage chance that any vortex monster hit by a wind blast is dispersed and instakilled. (Air elementals are immune to this, and they’re not vortices anyway.)

Teleport vortex, a monster which moves around the level sucking up items into its inventory; items in its inventory are periodically teleported randomly around the level. If it engulfs the hero, it will do the same.

Vortices confuse you after you spend a few turns engulfed in them, because you’re dizzy from spinning around so much. (Limit this to actual vortices: fog clouds, for instance, are in the v class but don’t spin you around.)

Smoke cloud monster (v), has a mild fire damage attack and a suffocating smoke attack. Generates in fiery areas.