Jack-in-the-Mox

{T}: Roll a six-sided die. This ability has the indicated effect.
1 — Sacrifice this artifact and you lose 5 life.
2 — Add {W}.
3 — Add {U}.
4 — Add {B}.
5 — Add {R}.
6 — Add {G}.

Acornelia, Fashionable Filcher

Whenever you cast a spell with a squirrel in its art, you get {A} (an acorn counter).
Whenever a Squirrel you control enters or dies, you get {A}.
{2}{B}, Pay X {A}: Target creature gets -X/-X until end of turn.
{G}, Pay X {A}: Target creature gets +X/+X until end of turn.

Stinging Scorpion

When this creature enters, target creature an opponent controls gets -1/-1 until end of turn.

Infernal Spawn of Evil

Flying, first strike
{1}{B}, Reveal this card from your hand, Say "It's coming": This card deals 1 damage to target opponent or planeswalker. Activate only during your upkeep and only once each turn.

Jumbo Imp

Flying
As this creature enters, roll a six-sided die. This creature enters with a number of +1/+1 counters on it equal to the result.
At the beginning of your upkeep, roll a six-sided die and put a number of +1/+1 counters on this creature equal to the result.
At the beginning of your end step, roll a six-sided die and remove a number of +1/+1 counters from this creature equal to the result.

Infernal Spawn of Infernal Spawn of Evil

Flying, first strike, trample
Once each turn, while you're searching your library, you may pay {1}{B}, reveal this card from your library and say "I'm coming, too" If you do, this card deals 2 damage to a player of your choice.

Inhumaniac

At the beginning of your upkeep, roll a six-sided die. On a 3 or 4, put a +1/+1 counter on this creature. On a 5 or higher, put two +1/+1 counters on it. On a 1, remove all +1/+1 counters from this creature.

Infernius Spawnington III, Esq.

Flying, first strike, trample, haste
This spell costs {3} less to cast for each card you've revealed this turn.
When this creature enters, you may say "I'm here." If you do, it deals 3 damage to target player.

Destroy target creature with reminder text. (Reminder text is any italicized text in parentheses that explains rules you already know.)

Snickering Squirrel

You may tap this creature to increase the result of a die any player rolled by 1.

Underdome

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

Enter the Dungeon

Players play a Magic subgame under the table, starting at 5 life and using their libraries as their decks. The winner searches their library for two cards, puts those cards into their hand, then shuffles.

Dirty Rat

When this creature enters, target opponent discards a card.

Skull Saucer

Flying
When this creature enters, destroy target creature and put your head on the table. Sacrifice this creature when your head stops touching the table.

Booster Tutor

Open a sealed Magic booster pack, reveal the cards, and put one of them into your hand. (Remove that card from your deck before beginning a new game.)

Hoisted Hireling

This creature has flying as long as it's being held above the battlefield.

Bat-

Flying
At the beginning of each end step, if an opponent lost 3 or more life this turn,
Augment {1}{B} ({1}{B}, Reveal this card from your hand: Combine it with target host. Augment only as a sorcery.)

Swamp

Poultrygeist

Flying
Whenever a creature dies, you may roll a six-sided die. If you roll a 1, sacrifice this creature. Otherwise, put a +1/+1 counter on this creature.