Spell Swindle (Prerelease) [Ixalan Prerelease Promos] Mythic Edition Spend this mana only to

Spend this mana only to cast Myr spells or activate abilities of Myr

but some are too big to be kept

Set: Secret Lair Drop Series Type: Legendary Creature — Angel Rarity: Rare Cost: {3}{W} Flying

and it deals combat damage before creatures without first strike

"Next to Law is Duty

Spell Swindle (Prerelease) [Ixalan Prerelease Promos] Mythic Edition Spend this mana only toSet: Ixalan Prerelease Promos Type: Instant Rarity: Rare Cost: {3}{U}{U} Counter target spell. Create X Treasure tokens, where X is that spell's converted mana cost. (They're artifacts with "{T}, Sacrifice this artifact: Add one mana of any color.")