Natural attacks against electricity-subtype creatures and AoO or AoO-like behavior

Question

So, I was working through an electricity-based dungeon I had written up rather off-the-cuff -- I was the DM, with the party consisting of a human Wiz3 and a wolverine (yes) Rogue3. One of the monsters in the dungeon is a tumblespark that I had straightforwardly backported from the PF SRD to use in this dungeon -- 3.5e itself doesn't stat any lightning elementals I know of.

However, wolverines, of course, like any other predatory animal in D&D, have the standard 'claw, claw, bite' set of natural attacks, and that was what our wolverine-rogue was using against the tumblespark. Should he have taken electricity damage on the tumblespark's attacks of opportunity for attempting to attack a lightning-subtype creature with a natural weapon, or does RAW prefer the interpretation I made at the time, which is that attacking a lightning-subtype creature with a natural weapon draws a standard melee attack of opportunity from that creature, not an energy-based attack of opportunity? Furthermore: does RAW even allow for energy-based AoOs from creatures that would sensibly use them, or does it force AoOs to be of one or more of the three mundane damage types (piercing, slashing, bludgeoning)? And could the tumblespark have burned its Arc ability for the round as an AoO, or must it use it on its own turn?

Answer 1

You've got a couple different issues here.

Natural Attacks don't provoke AoOs.

Natural attacks work basically like attacks with manufactured weapons. You don't provoke an attack of opportunity for making an attack with a natural weapon. Your player could make his 'claw, claw, bite' routine with impunity.

Tumblesparks don't deal energy damage with their normal attacks.

When you make an attack of opportunity, you simply make an attack with one of your available attack forms. For example, a fire elemental making an AoO would use its slam attack, which does bludgeoning and fire damage. Since tumblesparks only deal bludgeoning damage with their slam, they wouldn't deal electricity damage with an AoO.

Unless specifically called out, creatures only deal physical damage.

You ask about taking electricity damage from attacking an electricity-based creature. While some specific creatures have ways of damaging enemies that attack them, the general case is that, unless there is a specific ability that allows it, creatures don't deal damage to enemies attacking them, and they only do the damage types specified by their attack forms. It might seem weird to not take lightning damage when a living lightning bolt punches you, but that's the way the creature is written.

The tumblespark is poorly written.

You ask about discharging the 1/round Arc ability with an AoO. The tumblespark, like several of the elementals in the Tomb of Horrors guide, was written very poorly. There is no action given for how the tumblespark activates the Arc, which is not okay in a 3.x game. Also, it has a trample ability which causes lightning damage, and a slam that doesn't. It seems that there were several oversights made when making this creature, which make this a more confusing issue. I'd suggest adding an action required to Arc, even if it's just "As a free action on its turn". It could also be an immediate action, if you prefer.

Answer 2

The stat block you linked doesn't list a specific type for the tumblespark's slam attack, which means that it's going to be normal bludgeoning damage. Your interpretation that the attack of opportunity was a standard melee attack was correct.

Answer 3

The tumblespark would not get an Attack of Opportunity on the wolverine because the wolverine's claws are natural physical weapons and considered "Armed" Unarmed Attacks

"Armed" Unarmed Attacks Sometimes a character’s or creature’s unarmed attack counts as an armed attack. A monk, a character with the Improved Unarmed Strike feat, a spellcaster delivering a touch attack spell, and a creature with natural physical weapons all count as being armed.

When the tumblespark does get an Attack of Opportunity it's a melee attack so the attack type and damage would be as per the Melee stat block in the tumblespark's description. It could not use it's Arc special attack as the AoO.

Making an Attack of Opportunity

An attack of opportunity is a single melee attack, and you can only make one per round. You don’t have to make an attack of opportunity if you don’t want to.