msem-instigator

Flash
When Axom enters, remove up to three counters from target permanent.
{2}{U}: Return Axom to its owner's hand.

Whenever a player activates an ability that isn't a mana ability, Burning-Tree Shaman deals 1 damage to that player.

Whenever a card is put into a graveyard from anywhere, put a +1/+1 counter on Chief Striking Dawn.
{1}{B}{G}, Remove three counters from Chief Striking Dawn: Return a permanent card from your graveyard to the battlefield.

Whenever you cast an instant or sorcery spell, create a 1/1 red Alien creature token with “This creature can't block.”
{2}{R}, Sacrifice two Aliens: Copy target instant or sorcery spell you control. You may choose new targets for the copy.

[+1]: Haide Bankbuster deals 2 damage divided as you choose among one or two targets.
[+1]: Draw two cards unless any player has Haide Bankbuster deal 3 damage to them.
[–9]: Until end of turn, gain control of all permanents target player controls and they gain haste. Untap those permanents.

If one or more counters would be put on a permanent you control, you may have that many counters plus one or that many counters minus one put on that permanent instead.

Hexproof
Invisible Stalker can't be blocked.

(As you complete a condition, decode it. After all are decoded, you solve the mystery and transform this.)
When Mystery of the Crashed Craft enters, create two 1/1 red Alien creature tokens with “This creature can't block.”
{MG}—You cast an instant spell.
{MG}—You cast a sorcery spell.

Whenever Penny and Pete attacks, gain control of up to one target noncreature permanent and up to one target creature until end of turn. Untap the noncreature permanent, then tap the creature. It's attacking.

Each Rogue you control can't be blocked by creatures with greater power than it.
Whenever a Rogue deals combat damage to a player, gain control of target nonland permanent that player controls unless that player pays {1}.

Haste
Whenever Spellslinger Elf deals combat damage to a player, draw a card, then you may cast a card from your hand with mana value 3 or less without paying its mana cost.

[+2]: Create a 2/2 red Werewolf creature token with first strike and haste.
[–3]: Tanya deals 3 damage to each creature that's not a Wolf or a Werewolf.
[–8]: For each permanent your opponents control, that player sacrifices it unless they have Tanya deal 2 damage to them.

[+1]: Tanya, the Mooncursed becomes a legendary 3/1 red Werewolf creature with first strike until end of turn.
[–2]: Tanya, the Mooncursed deals 3 damage to target creature or planeswalker.
[–4]: Destroy target nonbasic colorless permanent.

Mountains you control have “{T}: Add {R}{R}.”
[+1]: Exile the top card of your library. You may play that card until the end of your next turn.
[–2]: Conjure six cards named Scorch. Shuffle them and your hand into your library, then draw two cards.