When Experimental Synthesizer enters or leaves the battlefield, exile the top card of your library. Until end of turn, you may play that card. {2}{R}, Sacrifice Experimental Synthesizer: Create a 2/2 white Samurai creature token with vigilance. Activate only as a sorcery.

When Kroxa enters the battlefield, sacrifice it unless it escaped. Whenever Kroxa enters the battlefield or attacks, each opponent discards a card, then each opponent who didn't discard a nonland card this way loses 3 life. Escape—{B}{B}{R}{R}, Exile five other cards from your graveyard. (You may cast this card from your graveyard for its escape cost.)

Whenever a player sacrifices a permanent, Mayhem Devil deals 1 damage to any target.

When Unlucky Witness dies, exile the top two cards of your library. Until your next end step, you may play one of those cards.

As an additional cost to cast this spell, sacrifice an artifact or creature. Draw two cards and create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")

Destroy target creature if it has mana value 2 or less. Revolt — Destroy that creature if it has mana value 4 or less instead if a permanent you controlled left the battlefield this turn.

({T}: Add {B} or {R}.) As Blood Crypt enters the battlefield, you may pay 2 life. If you don't, it enters the battlefield tapped.

If you control two or more other lands, Den of the Bugbear enters the battlefield tapped. {T}: Add {R}. {3}{R}: Until end of turn, Den of the Bugbear becomes a 3/2 red Goblin creature with "Whenever this creature attacks, create a 1/1 red Goblin creature token that's tapped and attacking." It's still a land.

Haunted Ridge enters the battlefield tapped unless you control two or more other lands. {T}: Add {B} or {R}.

If you control two or more other lands, Hive of the Eye Tyrant enters the battlefield tapped. {T}: Add {B}. {3}{B}: Until end of turn, Hive of the Eye Tyrant becomes a 3/3 black Beholder creature with menace and "Whenever this creature attacks, exile target card from defending player's graveyard." It's still a land.

({T}: Add {R}.)

{T}: Add {R}. Channel — {3}{R}, Discard Sokenzan, Crucible of Defiance: Create two 1/1 colorless Spirit creature tokens. They gain haste until end of turn. This ability costs {1} less to activate for each legendary creature you control.

({T}: Add {B}.)

{T}: Add {B}. Channel — {3}{B}, Discard Takenuma, Abandoned Mire: Mill three cards, then return a creature or planeswalker card from your graveyard to your hand. This ability costs {1} less to activate for each legendary creature you control.

Gain control of target creature with mana value 3 or less until end of turn. Untap that creature. It gains haste until end of turn.