You may choose not to untap Master of Minds during your untap step. {T}: Gain control of target creature with mana value X or less for as long as Master of Minds remains tapped, where X is the number of Islands you control.
Whenever you cast a spell, if it isn't your main phase, choose one. This ability triggers only once each turn. • Put a +1/+1 counter on Master of Three Paths. • Tap target creature. • Master of Three Paths phases out. (Treat it and anything attached to it as though they don't exist until its controller's next turn.)
When Master of the Abyss enters, draw two cards, then discard a card. {2}{U}{U}, {T}, Discard two cards: Create an X/X black Horror creature token, where X is the number of cards in your graveyard.
Experience (Whenever this creature attacks, if it has fewer than three +1/+1 counters on it, put a +1/+1 counter on it.) Whenever an experience ability puts a +1/+1 counter on a creature you control, put a +1/+1 counter on that creature.
When Matron of Machines dies, put a +1/+1 counter on up to one target creature. {3}{W}, Exile Matron of Machines from your graveyard: Create two 1/1 colorless Construct artifact creature tokens. Activate only as a sorcery.
Flash Reach Whenever Mattia enters or becomes tapped, put a +1/+1 counter on target creature you control. {2}{G}, {T}: Target creature must be blocked this turn if able. Activate only as a sorcery.
When Mausoleum Suffragan enters, create a white and black Aura enchantment token named Pale Shroud attached to target creature. The token has enchant creature and “Enchanted creature gets +1/+1 and has lifelink.” Whenever an artifact or enchantment you control enters, each opponent loses 1 life.
Reach When Mawdryk's Harrier enters, look at the top six cards of your library. You may put an Elf card with lesser mana value from among them onto the battlefield. Put the rest on the bottom of your library in a random order. Other Elves you control get +1/+1.
Mechanized Ideal gets +X/+Y, where X is the highest base power among other creatures you control and Y is the highest base toughness among other creatures you control.
Artifact vision (Whenever this or another artifact you control enters, reveal the top card of your library. Then you may put that card into your graveyard.) Whenever Mechanomind Researcher envisions an artifact card, put a +1/+1 counter on it.
Flying {2/B}{2/B}, {T}, Sacrifice Meddling Gargoyle: Target opponent reveals their hand. You choose a nonland card from it. That player discards that card. Activate only as a sorcery.
If you would create an Army token while Mehr's Unending Horde is in your graveyard, you may instead return Mehr's Unending Horde from your graveyard to the battlefield. Counters remain on Mehr's Unending Horde as it moves to any zone other than a player's hand or library.