Countering doesnt affect the demonstrate trigger because its a cast trigger

Merciless Rage Commander (1) Planeswalker (1) Creatures (28) Chainer, Nightmare Adept Greven, Predator Captain Anje's Ravager Archfiend of Spite Asylum Visitor Big Game Hunter Bloodhall Priest Bone Miser Champion of Stray Souls Doomed Necromancer Flayer of the Hatebound Geth, Lord of the Vault Gorgon Recluse Grave Scrabbler K'rrik, Son of Yawgmoth Magus of the Wheel Meteor Golem Nightshade Assassin Overseer of the Damned Plaguecrafter Sanitarium Skeleton Scaretiller Skyfire Phoenix Solemn Simulacrum Soul of Innistrad Squee, Goblin Nabob Stromkirk Occultist Wildfire Devils Instants (4) Chaos Warp Dark Withering Fiery Temper Violent Eruption Sorceries (12) Alchemist's Greeting Avacyn's Judgment Boneyard Parley Beacon of Unrest Call to the Netherworld Hate Mirage From Under the Floorboards In Garruk's Wake Malevolent Whispers Mire in Misery Murderous Compulsion Nightmare Unmaking Enchantments (6) Curse of Fool's Wisdom The Eldest Reborn Faith of the Devoted Hedonist's Trove Warstorm Surge Zombie Infestation Artifacts (8) Aeon Engine Armillary Sphere Bloodthirsty Blade Grimoire of the Dead Hedron Archive Key to the City Rakdos Locket Sol Ring Lands (40) Akoum Refuge Ash Barrens Barren Moor Bloodfell Caves Cinder Barrens Command Tower Drownyard Temple Evolving Wilds Exotic Orchard Forgotten Cave Geier Reach Sanitarium Memorial to Folly Mortuary Mire Myriad Landscape Rakdos Carnarium Rakdos Guildgate Rix Maadi, Dungeon Palace Sanctum of Eternity Temple of the False God Terramorphic Expanse Mountain x10 Swamp x10 The Commanders Anje Falkenrath enables this deck's madness theme perfectly

Other than that, I wasn't sure what to bring, because I don't usually make Rakdos decks
All versions of Mewtwo cards (9) All Mewtwo cards currently available in Pokmon TCG Pocket, including different variations and rarities
Drawing a card is amazing, too, because it helps keep your hand full