Paraelementals are a group of new elementals in dNetHack that use the E symbol, but extend past earth, air, fire, and water. Note that the E class in dNetHack also includes stalkers, dream quasielementals, and a couple of other monsters. Paraelementals have element-based attacks based on their type, but vary in speed and damage depending on the element.
Lightning paraelementals are likely the most lethal of the elementals to an early-game character. Both the passive and touch attack damage are only halved by shock resistance, not totally negated, and capable of destroying items in your inventory.
Lightning paraelementals can be sung into being by blue half-dragon bards.
Poison paraelementals aren't very threatening to a character with poison resistance, but can seriously injure one without. Poison instadeath has been removed, but the "debilitating" poison that replaces it will severely drain your constitution. Both the passive and touch attack damage are only halved by poison resistance, not totally negated.
Poison paraelementals can be sung into being by green half-dragon bards.
Ice paraelementals are slow, but have very damaging attacks. Cold resistance halves the damage taken, but doesn't fully negate it, and it's still capable of destroying inventory items without extrinsic cold resistance. However, cold paraelementals are very slow and normally avoidable if needed.
Ice paraelementals can be sung into being by white half-dragon bards.
Acid paraelementals can be dangerous without acid resistance, but aren't quite as damaging as ice paraelementals. They're quite slow as well. However, both their passive attack and their touch attack can corrode your weapon and armor if it's not fixed. Just like the other paraelementals, their damage is only halved by acid resistance.
Acid paraelementals can be sung into being by yellow half-dragon bards.