Slaughter Pact Slaughter Pact is an acceptable removal spell that you can fire off for zero mana

Adaptive Sporesinger Additive Evolution Alacrian Jaguar Ancient Adamantoise Animus of Predation Apothecary Stomper Appeal // Authority Awakened Skyclave Beacon Behemoth Bear with Set's Mechanic (playtest) Big Bertha Bighorner Rancher Bitterbow Sharpshooters Brambleguard Veteran Briarbridge Tracker Brushstrider Built Bear (playtest) Cemetery Prowler Chancellor of the Tangle Circle of Elders Cryptid Inspector Curious Altisaur Deepwood Denizen Diplomatic Relations Dire-Strain Brawler Dragon Sniper Earthbending Student Earthrumbler Elder Gargaroth Elfhame Wurm Embodiment of Insight Emeritus of Abundance End-Raze Forerunners Enduring Vitality Esika, God of the Tree Excavating Anurid Fangorn, Tree Shepherd Feasting Troll King First Responder Flycatcher Giraffid Galewind Moose Gamma Grotesque Gargos, Vicious Watcher Garruk's Warsteed Gatebreaker Ram Giant Beaver Glacier Godmaw Gnarled Grovestrider Gnarled Sage God-Eternal Rhonas Goldvein Hydra Gorm the Great Grabby Tabby Greenwood Sentinel Guardian of the Great Conduit Haldir, Lrien Lieutenant Harmonious Emergence Harold and Bob, First Numens Hercules, Prince of Power Heronblade Elite Hierophant Bio-Titan Hit-Monkey Honor Troll Honored Hierarch Howl of the Hunt Howling Galefang Hulkling, Burgeoning Bruiser Interplanar Brushwagg (playtest) Invoke the Ancients Jewel Thief Joraga Bard Kamahl's Will

For just 3RR, this Dragon had hard-hitting, efficient stats as a 5/5 with flying and haste, but what made it a true mythic rare was its formidable enter-the-battlefield effect
This is a very common misconception, because they feel similar (I can pay this cost instead of normally casting the spell), but they are activated abilities
The more layers of protection you give it, the better