Ah! Decisions! Cards like this that have contrasting abilities are awesome for that reason to make me think but sometimes they also make my brain hurt. :P

I like it. It's a nice tweak on Ball Lightning: it gets to sit around until it hits someone, but it won't trample if you have anything else.

I like it too, it belongs in a dedicated burn deck, 4 of these & 4 Ball lightnings being the only creatures - fun.

I wonder if it would work just as well being "the only creature attacking" because I think that way I would like it more. You still get the bonus for it being the only creature but makes a harder choice to utalize the trample ability if one has other creaturs to attack with also.

One of the themes within the set is the allowance of nihilism; that is, one of the factions in the set's story is a group of nutjobs that believe the world has already ended, and they're trying to take apart the last "false pretenses" that keep it from becoming the true void they think it's all supposed to be. They're batshit crazy. As such, they don't really want to organize in any way. They're anarchists like that, and to me it felt like the best way to show that visually was to present cards that seem to work best in total isolation.

MAGIC, by it's nature, has certain rules that make it what it is. Creating a group that has no rules within the game is tricky. I need to be able to bend certain things in order to make the story piece work within the game structures. Changing the way a player approaches the use of a card is fair game so long as the card is still fun enough that people want to play it.

In this case, expressing the nihilism has to be done at a level that makes sense in an uncommon slot. You'll notice that very few of the common cards really embrace this philosophy (Indolent Stubbleback is the most obvious one). That's because mechanically, a limited format environment can't handle having multiple cards that say "play me all by myself", and conveniently also because in the story, the nihilists are fringe players in the overall cultural map of Debronia and the Soradyne Corporation.

That said, I feel like this card needs to be slightly adjusted. I'm dropping the power by one, further making it the "in-between" of Ball Lightning and Lightning Elemental.

In order for the sacrifice clause to really mean much of anything, you're going to have to raise its toughness, otherwise you just have this clause that works in opposition to the basic function and stats of the card. By which I mean, the P/T imbalance, haste, and conditional trample all scream "ATTACK WITH THIS CARD IMMEDIATELY, YOU'RE BIG RED", but because it can't actually survive combat with a creature under most circumstances, the sac clause is just there to allow uncharacteristic defense.

As a 5/3, the text would seem more rational and be a bit more in line with the traditional body types of a Hellion.

Actually, with the Feint ability in the set, it does have relevance.

While I can see your point, that strikes me as representing a very uncomfortable tension. Assuming you have a feint spell in hand, your Crackling Hellion represents either 5 damage or ~5 colorless mana, except if you use that mana to cast a feint creature you no longer have trample. Alternatively, if you use it to cast a spell, you're probably casting something like (((Firebomb))). At which point you're giving your opponent an additional turn to eliminate your fragile creature. Obviously, not every spell should represent an easy decision, but it's certainly a bit more evaluative processing than I think is typical for this type of card.

Another way to look at this is that you've introduced an unexpected clause to suit your new ability, rather than allowing the new ability to adjust how players use traditional cards.

Reworked to better mesh with both "swarm" and "nihilist" factions. Dropped to common.

The cardname and the name in the textbox don't match.

As core set gets Arc Runner, I'd like to think this could be pushed ever so slightly. Something like "If CARDNAME is the only creature on the battlefield, it gets +2/+2."

True nihilists don't let their opponent's creatures live either.

EDIT - Admittedly, Arc Runner didn't have any sort of logical archetypes to actually doing anything in, so maybe Arc Runner was "pushed" already.

Arc Runner also dies at EOT, and I took that clause off the hellion. I debated givin him +2/+0 for being solo, but I'm hesitant to make a dude better than Lightning Elemental in a ponza/RDW deck at 3 mana.

Ah, yeah, my brain wasn't quite processing the totality of the edit and spaced on how it isn't a Ball Lightning variant anymore.