Firstly, I was excited to use IcyCatElf's glass energy orbs before realizing they were only available in the sizes used for energy icons on the Pokémon themselves, and wouldn't be large enough for a Special Energy. I tried magnifying the symbols with these tools--
https://app.remini.ai/result?gclid=...e&taskId=1bf306b7-161c-44b4-87bf-05ade4d90978
--but it didn't come out the way I was hoping it would, so I settled on TylerComfeyHat's Energy symbol. It actually looks cleaner now, though it doesn't look as pretty as PMJ's Star Energy.
Now for the background. The card is based on the ability Protean. This Hidden Ability has been given to three Pokémon lines. The rationale for this ability seems to be an improvement on Kecleon's Color Change by handing you (the trainer) the reins in changing its type to suite your needs. However, I was surprised to find that Kecleon didn't actually have a Hidden Ability in Generation 5, meaning it received this Ability for the first time... alongside Greninja. Now, Meowscarada (I didn't just type "Meowstic,"
you just typed "Meowstic") is the third line to receive this Ability. And then there's Cinderace with Libero, it's "Protean at home."
Essentially this Special Energy, which, like most Omnium cards, is designed for circa 2010/2011 (DPPt/HGSS/BW), will give your Pokémon the Ability Protean. This card would work well with Pokémon with the attack Rotating Claws, which, in 2010, probably means Registeel LA (which, incidentally, has a built-in mechanism for discarding those Energy). Incidentally, 50 damage and the ability to hit any Weakness means that Registeel can OHKO many of the powerful basics in the format, especially Pokémon SP and many of the legendaries coming out of sets like Legends Awakened. In other words, most basics with a weakness of 2x (instead of +20, which many legendary Pokémon seem to have). Unfortunately, Energy Gain will help those SP's out-speed Registeel most of the time, though you can still use Regi Heal to keep Registeel healthy to a limited extent.
But this isn't about Registeel. This is about what card
you, the player,
create to go with it.
As for what existing cards make this card worth playing, this card will also go well with the SP decks themselves, since they already run multiple types of basic Energy, but thanks to the Special Energy clause, this card isn't going to allow you to turn Dialga G Lv.X into a multitype tank that can abuse both Protean Energy
and Special Energy. (I wish I could say I did that on purpose; I only realized the connection just now as I was writing the description.) Keep in mind that you'll have to be more careful with your Call Energy if you want to use this card later in the game. Consider planning on retreating or using Dragon Rush to bump an unwanted Call Energy if you're forced to attach it to a Pokémon you will want to attack with later.
Out of evolving Pokémon decks, Flygon is probably the one that will be able to utilize this card the best, since they will want to run multiple types of basic Energy to help Pokémon retreat for free anyways. Decks like Abomasnow/Ampharos and Gardevoir/Gallade can benefit as well, although they may just prefer to use whatever attacker is already up front. Steelix Prime is right out for the reasoned outlined under Dialga G Lv.X (see a theme here?). Cards like Donphan Prime and Kingdra (both the LA and Prime versions), which are fairly bulky and have low attack costs with high output, may come to love this card, so it could spawn some new archetypes using these sorts of cards. Come to think of it, those two Pokémon were already featured in a deck together, so that works just swimmingly. (Wait,
can elephants swim with that low a center of gravity?)
And Regigigas... we don't talk about Regigigas.
...
However, since I want to get a good score, I guess we're talking about Regigigas anyways. You won't be able to attach this card to Regigigas Lv.X with Sacrifice, but if you can attach it manually, Regigigas will be able to hit for at least 3 weaknesses (4, I guess, because the list I'm looking at right now runs a Psychic Energy, evidently so Azelf can use Lock Up to trap something in the active spot). Of course, Gaia blast already does plenty of damage (collateral as well as militant) with Expert Belt as it is, so Protean Energy probably won't help Regigigas hit
that many relevant numbers, but it has the option available.
Keep in mind this effect overrides it’s existing type. If you attached a Lightning Energy and a Protean Energy to Yanmega Prime, for example, that Pokémon would be a Lightning type, and could Knock Out another Yanmega in a single hit if you have a Judge in hand. (Technically Yanmega was released just after 2010 Worlds, but still within the vague Omnium era.)
Hopefully that's a good place to get your creative juices flowing! Just remember, though, you're allowed to appropriate this card for later eras, per Jabberwock's FAQ post, so feel free to create a card for another era if you can see a use for it there! (Also, theoretically, you could use this card for an era
prior to when it was created. Would that be legal,
@Jabberwock?) (Come to think of it, this card would be very fun in the ex era, when some Pokémon had multiple weaknesses. Although I'm pretty sure Onmium does that as well.
References:
Weakness Guard Energy ("This card provides [C] Energy.")
Dragonium Z: Dragon Claw ("If the Pokémon this card is attached to has")
Gligar UNB ("has no [Special] Energy attached to it")
Lycanroc CEC ("Special Energy attached to it")
Mismagius SM245 ("that Pokémon is")
Rowlet & Exeggutor GX ("if that Pokémon")
Drampa CEC ("If [that] Pokémon has 2 or more different types of basic Energy attached to it,")
Kecleon CRE ("each of those types") (I pruned the reference down to the point where I couldn't find any more Sun and Moon era references)
P.S. You can see the original Special Energy as an attachment beneath the spoiler with the original Energy. Not only did the slightly rainbow-tinted orb feel a little too busy, distracting from the otherwise simple contrast of dark and light shades), but it was also too low a resolution. Worse, however, the wording seemed to imply that it was the
Energy changing type, rather than the
Pokémon. This error, for reasons obvious to all, needed to be corrected. Otherwise, the card would essentially be a nerfed Crystal Energy (as if the Rainbow Energy successor hadn't been nerfed enough).