msem-instigator

Enchant creature
Enchanted creature gets +1/+0 and has menace and “{1}{R}: This creature gets +1/+0 until end of turn.”

Battalion — Whenever Barbarian Rager and at least two other creatures attack, Barbarian Rager gets +2/+0 until end of turn.

Other Warriors you control have first strike.
Other Barbarians you control get +1/+0.

Deathtouch
Whenever a creature dealt damage by Barbed Beast this turn dies, transform Barbed Beast.

Vigilance, deathtouch
Whenever a creature dealt damage by Barbed Bruiser this turn dies, draw a card.

Barbed Reef enters tapped. When it does, it explores. (Reveal the top card of your library. Put that card into your hand if it's a land. Otherwise, put a +1/+1 counter on this, then you may put that card into your graveyard.)
{T}: Add {B}.
{4}{B}: Barbed Reef becomes a Jellyfish creature. (This effect lasts indefinitely.)

Put X +1/+1 counters on target creature you control. It deals damage equal to its power to up to one target creature or planeswalker you don't control. If that creature or planeswalker would die this turn, exile it instead.

When Barhopping in Minei enters, draw up to four cards, then put twice that many drink counters on Barhopping in Minei.
Your maximum hand size is reduced by the number of drink counters on Barhopping in Minei.

Choose one —
• Destroy target artifact or enchantment.
• Barkcrush deals 5 damage to target creature with flying.

When Barking Irons enters, if it's not a token, create a token that's a copy of it.
Equipped creature gets +2/+0.
Equip {2}

Equipped creature gets +2/+2.
Equip {3}

Equipped creature gets +1/+1 for each permanent attached to it and has trample.
Equip {4}

Barren Boneyard enters tapped.
{T}: Add {B}.
{2/B}{2/B}: Barren Boneyard becomes a 2/3 black Elemental creature with deathtouch until end of turn. It's still a land.

As Barren Desolation enters, you may pay 2 life. If you don't, Barren Desolation enters tapped.
{T}, Sacrifice Barren Desolation: Search your library for a Plains or Swamp card, put it onto the battlefield, then shuffle.

Barren Vista enters tapped.
{T}: Add {U} or {B}.
{1}, {T}: Add one mana of any color.

When Barricade Patrol enters, create a 1/1 white Human Soldier creature token.
Whenever another creature you control dies, Barricade Patrol deals 1 damage to target player.

Each planeswalker you control enters with an additional loyalty counter on it.
{T}: Add {C}.

Whenever you untap a nonland permanent, put a winding counter on Barton's Pocketwatch.
{T}: Look at the top card of your library. You may put it into your graveyard. Then if Barton's Pocketwatch has twelve or more winding counters on it, exile it and take an extra turn after this one.

Protection from multicolored
[+2]: Create a colorless artifact token named Mind Stone with “{T}: Add {C}” and “{1}, {T}, Sacrifice Mind Stone: Draw a card.”
[–3]: Create Barxbot 9000, a legendary 6/4 colorless Construct artifact creature token with “All damage that would be dealt to Barx planeswalkers you control is dealt to this creature instead.”
[–12]: You and target opponent each gain control of each permanent the other controls that's one or more colors.

As an additional cost to cast this spell, exile a noncreature artifact you control with mana value X until Barx leaves the battlefield or fails to resolve. X can't be 0.
[+1]: Exile the top card of your library. You may play it until you exile another card with Barx.
[–3]: Create an X/X colorless Hound artifact creature token, where X is the greatest mana value among cards exiled by Barx as you activate this ability.
[–10]: Search each player's library for any number of nonland cards with total mana value 10 or less and exile them, then those players shuffle. Cast those cards without paying their mana costs.

Choose one —
• Target creature gets +2/-1 until end of turn.
• Basat Charm deals 3 damage to target player or planeswalker.

Menace
Cat creatures you control have menace.
When Basat Priest enters, create a 2/2 white Cat creature token.

Basin Fortress enters tapped unless you control a basic land.
{T}: Add {B} or {G}.

Discard your hand, then draw three cards. Bask in Fire deals 2 damage to each creature.