Tried to follow that link, and it closed my browser and asked me to sign into an account. Not gonna lie, that feels a little shady.

Zec'rzt, Plague of All

Legendary Planeswalker - Zec'rtz

Affinity for Plains, Mountains and Swamps

+2 Deal 1 damage to each player for each Creature in that player's graveyard. You gain that much life.

+1 Each opponent sacrifices a creature unless they lose 3 life. You gain life equal to the amount of life lost in this way.

-2 Until end of turn, creatures you control get +1/+0 for each creature in all graveyards, and gain Fear, Lifelink and Menace.

-10 You get an emblem with "Whenever a creature enters a graveyard from anywhere, each opponent loses 3 life. You gain life equal to the amount of life lost in this way."

7

This will never fit on cardboard (btw, prove me wrong if you want to by using your imaging skills to post a proper version of this with a picture), but I believe it fits the challenge. I see Zec'rzt as being a Lhurgoyf Planeswalker from Lorwyn. Don't know why, that just seems to fit.

If you think this doesn't meet the challenge, then repeat. If so, then make a Commander that this card would go into the 99 for.

Ninja'd, So I'll give Timmy the choice.

Rebarbative Heat

Enchantment

At the beginning of your upkeep, Rebarbative Heat deals 1 damage to each creature you control

Creatures can't attack you or Planeswalkers you control unless their controller pays , where X is half the number of Mountains you control, rounded down. If X is 5 or more, Rebarbative Heat deals 5 damage to that creature.

I picture this as a zone of temperature filling your defensive side of the battlefield, with a base temperature of 75° fahrenheit, which increases by 10° for each mountain you control. From example, 3 mountains equals 105°. 6 mountains equals 135°. 10 mountains, which is what gets you to X=5, equals 165°, which would be 73.8° Celsius, for any of y'all not in the States. That's almost hot enough to smoke a brisket.

Next challenge: Make a cost equipment that equips to a land and allows the land to produce extra mana, but not immediately.