Whenever an opponent casts a spell, you may draw a card unless that player pays .

: Add one mana of any type that a land you control could produce.

At the beginning of your upkeep, flip a coin. If you lose the flip, this artifact deals 3 damage to you.
: Add .

: Draw three cards.
: Return Arcanis to its owner's hand.

: Add .
, , Sacrifice this land: Create X Treasure tokens.

If an effect would create one or more tokens under your control, it creates twice that many of those tokens instead.

If a player would draw a card, that player exiles that card face up instead.
Each player may play lands and cast spells from among cards they exiled with this artifact this turn.

This spell costs less to cast, where X is the greatest power among creatures you control.
: Add . You gain 2 life.
Whenever a nontoken creature you control enters, put a +1/+1 counter on it and draw a card.

Horsemanship (This creature can't be blocked except by creatures with horsemanship.)

Equipped creature gets +2/+2.
As long as equipped creature is legendary, it has hexproof. (It can't be the target of spells or abilities your opponents control.)
Equip

This spell costs less to cast, where X is the greatest number of artifacts an opponent controls.
Flying, trample, haste
Whenever this creature deals combat damage to a player, you create a Treasure token for each artifact that player controls.

At the beginning of your upkeep, you may put a fuse counter on this artifact.
, Sacrifice this artifact: Destroy each artifact and creature with mana value equal to the number of fuse counters on this artifact.

During each of your turns, you may play a land and cast a permanent spell of each permanent type from your graveyard. (If a card has multiple permanent types, choose one as you play it.)

, Pay 1 life, Sacrifice this land: Search your library for a Swamp or Forest card, put it onto the battlefield, then shuffle.

When Battle Myrsphere enters the battlefield, reveal cards from the top of your library until you reveal a battle card. Put it onto the battlefield, and the rest on the bottom of your library in a random order.
Whenever Battle Myrsphere attacks, you may tap X untapped battles you control (so they're oriented like a regular Magic card). If you do, Battle Myrsphere gets +X/+0 until end of turn and deals X damage to the player or permanent.

Haste
: Create a token that's a copy of target nonlegendary creature you control, except it has haste. Sacrifice it at the beginning of the next end step.

, Pay 1 life: Add or .
, : Mount Doom deals 1 damage to each opponent.
, , Sacrifice Mount Doom and a legendary artifact: Choose up to two creatures, then destroy the rest. Activate only as a sorcery.

, , Sacrifice this artifact: Add one mana of any color. Draw a card. (Activate only as an instant.)

: Add .
Channel — , Discard this card: Return target artifact, creature, enchantment, or planeswalker to its owner's hand. This ability costs less to activate for each legendary creature you control.

: Add for each Forest you control.