Mana Echoes (218) [Onslaught] ICE you may add an amount

you may add an amount of {C} equal to the number of creatures you control that share a creature type with it

Friends teach what you want to know

Set: League Tokens 2015 Type: Token Creature — Monk Rarity: Common Prowess

Set: Portal Three Kingdoms Type: Creature — Ox Rarity: Uncommon Cost: {3}{G} Swampwalk (This creature can't be blocked as long as defending player controls a Swamp

Whenever an opponent casts a creature or planeswalker spell with the same name as a card in their graveyard

Mana Echoes (218) [Onslaught] ICE you may add an amountSet: Onslaught Type: Enchantment Rarity: Rare Cost: {2}{R}{R} Whenever a creature enters the battlefield, you may add an amount of {C} equal to the number of creatures you control that share a creature type with it. When the ground is saturated with mana, even the lightest footstep can bring it to the surface.