I really don't know how to word this.

What's a Mono-Creature?

As in an artifact creature, enchantment creature or land creature. Even planeswalker creature.

"Destroy target creature if it has another card type. (The card types are artifact, creature, enchantment, instant, land, planeswalker, sorcery, and tribal.)"

Or:

Choose one —

• Destroy target artifact creature.

• Destroy target enchantment creature.

• Destroy target land creature.

I was about to say "But that wouldn't work on Gideon", before I remembered he's always indestructible...

Doesn't Sarkhan become a non indestructible creature?

Alternatively, "Destroy target creature if it's an artifact, enchantment, or land."

Personally, I wouldn't bother with Planeswalker Creatures, since are no permanents printed with that type line. That, and when a Planeswalker becomes a creature, it still feels like just a planeswalker to me.

BTW, with these restrictions this card is also in Green's pie.

ROFL. Yes, it's hilarious that this could also be green.

Maybe "Destroy target artifact creature, enchantment creature, or land creature" would be simplest? Like "destroy target artifact or enchantment".

I'd like to include planeswalkers, but not enough to spell it out if it will rarely come up. FWIW, two gideon and one sarkhan become indestructible creatures, and two gideons become "prevent all damage" creatures, so it could matter, but rarely.

Or, don't actually do this, but my Melvin likes the idea, it could say "target artifact, creature or land gets -9/-9 UEOT" :)

@izaac: Sarkhan, the Dragonspeaker stops being a planeswalker when he becomes a creature ;)

And Jack's comment reminds me now of Piqued Fires :)

Oops, yes. Although, huh, if it did say "target planeswalker gets -9/-9 UEOT", could you cast that on Sarkhan in response to its become-a-creature trigger and have it have the desired effect?

Surprised piqued fires wasn't one of mine :) I often think it be interesting and simplify templating to allow damage and other effects to target anything, and just have no effect if the target isn't compatible. Like, "deal 3 damage to target player or permanent", which suddenly is useful when they later print the first planeswalker :)

How about this?

Mixing that weird restriction with that hacky kill style seems like doubly wrong.

I actually like Piqued Fires very much. Just add a reminder text with something like "Damage can’t be dealt to a permanent that’s neither a creature nor a planeswalker" and you got a serious cool card.