Brainiac

Garbage Elemental

Cascade (When you cast this spell, exile cards from the top of your library until you exile a nonland card that costs less. You may cast it without paying its mana cost. Put the exiled cards on the bottom in a random order.)
When Garbage Elemental enters, roll a six-sided die. Garbage Elemental deals damage equal to the result to target opponent or planeswalker.

Target Minotaur

Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)

Bumbling Pangolin

When this creature enters, you may destroy target artifact.

Half-Orc, Half-

Trample
At the beginning of each end step, if an opponent was dealt damage this turn,
Augment {1}{R}{R} ({1}{R}{R}, Reveal this card from your hand: Combine it with target host. Augment only as a sorcery.)

Border Guardian

Whenever you cast a silver-bordered spell, put a +1/+1 counter on Border Guardian.
Whenever you cast a black-bordered spell, Border Guardian can't be blocked this turn.
Whenever you cast a white-bordered spell, Border Guardian gains double strike until end of turn.

Urza, Academy Headmaster

+1: Head to AskUrza.com and click +1.
−1: Head to AskUrza.com and click -1.
−6: Head to AskUrza.com and click -6.

City of Ass

City of Ass enters tapped.
{T}: Add one and one-half mana of any one color.

Hammer Helper

Gain control of target creature until end of turn. Untap that creature and roll a six-sided die. Until end of turn, it gains haste and gets +X/+0, where X is the result.

Three-Headed Goblin

Triple strike (This creature deals first-strike, regular, and last-strike combat damage.)

Super-Duper Death Ray

Trample (This spell can deal excess damage to its target's controller.)
Super-Duper Death Ray deals 4 damage to target creature.

Exotic Orchard

{T}: Add one mana of any color that a land an opponent controls could produce.

Underdome

{T}: Add {C}.
{T}: Add one mana of any color. Spend this mana only to pay Un-costs.

It That Gets Left Hanging

When It That Gets Left Hanging enters, ask a person outside the game to high-five you. If they won't, It That Gets Left Hanging gains haste until end of turn.

Painiac

At the beginning of your upkeep, roll a six-sided die. Painiac gets +X/+0 until end of turn, where X is the result.

Deal Damage

Deal Damage deals 4 damage to any target.
Gotcha — If an opponent says "deal" or "damage," you may say "Gotcha!" When you do, return Deal Damage from your graveyard to your hand.

Ol' Buzzbark

When Ol' Buzzbark enters, roll X six-sided dice onto the battlefield from a height of at least X inches. For each die, put a number of +1/+1 counters equal to the result on each creature you control that die is touching. For each die, Ol' Buzzbark deals damage equal to the result to each creature an opponent controls that die is touching.

Buzzing Whack-a-Doodle

As Buzzing Whack-a-Doodle enters, you and an opponent each secretly choose Whack or Doodle. Then those choices are revealed. If the choices match, Buzzing Whack-a-Doodle has that ability. Otherwise, it has Buzz.
• Whack — {T}: Target player loses 2 life.
• Doodle — {T}: You gain 3 life.
• Buzz — {2}, {T}: Draw a card.

"Ach! Hans, Run!"

At the beginning of your upkeep, you may say "Ach! Hans, run! It's the . . ." and the name of a creature card. If you do, search your library for a card with that name, put it onto the battlefield, then shuffle. That creature gains haste. Exile it at the beginning of the next end step.

Face to Face

You and target opponent play a best two-out-of-three Rock, Paper, Scissors match. If you win, Face to Face deals 5 damage to that player.

The Big Idea

{2}{B/R}{B/R}, {T}: Roll a six-sided die. Create a number of 1/1 red Brainiac creature tokens equal to the result.
Tap three untapped Brainiacs you control: The next time you would roll a six-sided die, instead roll two six-sided dice and use the total of those results.

The Countdown Is at One

Players play a Magic subgame, starting at 1 life and using their libraries as their decks. For the rest of the main game, if a source would deal damage to a player who didn't win the subgame, it deals double that damage to that player instead.

Mountain

Just Desserts

Just Desserts deals π damage to target creature. (π is the ratio of a circle's circumference to its diameter. (It's a smidgen more than 3.))