Frightful Desperation: Mechanics

harmonize: Add the full rule text of the harmonized card to the spell on the stack it is harmonized to, choosing any required extra targets while doing so Used on 0 cards:

Combine spells

: When you cast this spell from your hand, copy each Jewel you own in exile. You may cast the copies. Exile this spell as it resolves. Used on 9 cards: Scarlet Sapphire, Corrupted Diamond, Sylvan Aquamarine, Lichen-covered Obsidian, Lucent Turquoise, Crow Blood Ruby, Blood of the Countess, Ferrous Emerald, Unassuming Pebble

A type of sorceries/instants that can be joined together

Forbidden: When you cast this spell, exile it with PARAM1ASWORDS seal counters on it. Used on 2 cards: Bazaarine Scroll, Flagellant's Scroll

For spells that are immediately exiled upon being cast

Eternal: Exile this spell as it resolves. For the rest of the game, you can't cast spells and you can activate this card's activated abilities. Used on 5 cards: Everlasting Submission, Infinite Brightness, Unending Barrage, Boundless Regrowth, Limitless Decay

On spells that give you an activated ability for the rest of the game, at the cost of disallowing you to cast spells

Bloodfest: until end of turn, whenever a creature dies, copy this spell except for its bloodfest ability. Used on 4 cards: Revitalizing Infestation, Lingering Rage, Senseless Vengeance, Soul Extraction

Payoff for creatures dying

Bloodfest: when this permanent enters the battlefield, until end of turn, whenever a creature dies, copy this spell except for its bloodfest ability. Used on 1 cards: Red Goo

Same as bloodfest, but with remainder altered for permanents

Revenant: X must be the number of times you cast a spell named "~" this game. Used on 3 cards: Lich Acolyte, Flaming Apparition, Mana Ladder

Relapse: For the rest of the game, whenever you cast an instant or sorcery spell, throw a six-sided die. On a six, that spell becomes a copy of ~ except for its Relapse ability, and you may choose new targets for it. Used on 1 cards: Erotophonophilia

A sort of monkey-paw recursion

Stealth: Spells and abilities that don't target this permanent can't destroy, exile or damage it, nor they can cause counters to be put on, or removed from, it. Used on 1 cards: Lurking Smiler

Shields from most mass spells etc

Amass: Put PARAM2ASWORDS +1/+1 counters on an Army you control. If you don’t control one, create a 0/0 black PARAM1 Army creature token first. Used on 0 cards:

Like amass, but not limited to zombies

In card text or details pages, write the mechanic's code name (playtest name) between square brackets, like "[Crittercast]", "[Bushido 1]" or "[Delay 4 {2}{R}{R}]". It will be expanded to the mechanic's name plus reminder text, such as "Suspend 4 – {2} {r} {r} . (Rather than cast this spell from your hand,...)"
To expand a mechanic's name but not its reminder text, include parentheses at the end of the square brackets: "[Crittercast()]", "[Delay 9 {R}()]".