So Mewtwo's moves contradict each other in a way since the first move makes the defending Pokemon fall asleep and then the second move is better if the defending Pokemon has a lot of energy cards on it, if my Pokemon is asleep I wouldn't attach any energy cards to it, so if you put the defending Pokemon asleep right away Psychic will probably only do minimal damage each turn instead of more than 40 each turn

Acidic Sliver Armor Sliver Barbed Sliver Basal Sliver Battering Sliver Battle Sliver Belligerent Sliver Blade Sliver Bladeback Sliver Blur Sliver Bonescythe Sliver Bonesplitter Sliver Brood Sliver Capricious Sliver Cautery Sliver Cleaving Sliver Clot Sliver Cloudshredder Sliver Constricting Sliver Crypt Sliver Crystalline Sliver Darkheart Sliver Dementia Sliver Diffusion Sliver Dormant Sliver Dregscape Sliver Enduring Sliver Essence Sliver Firewake Sliver First Sliver's Chosen Frenetic Sliver Frenzy Sliver Fungus Sliver Fury Sliver Galerider Sliver Gemhide Sliver Ghostflame Sliver Groundshaker Sliver Harmonic Sliver Hatchery Sliver Heart Sliver Hibernation Sliver Hollowhead Sliver Homing Sliver Horned Sliver Hunter Sliver Lancer Sliver Lavabelly Sliver Lazotep Sliver Leeching Sliver Lymph Sliver Magma Sliver Manaweft Sliver Megantic Sliver Mesmeric Sliver Metallic Sliver Might Sliver Mindlash Sliver Mindwhip Sliver Mistform Sliver Mnemonic Sliver Muscle Sliver Necrotic Sliver Opaline Sliver Plague Sliver Plated Sliver Poultice Sliver Predatory Sliver Psionic Sliver Pulmonic Sliver Quick Sliver Quilled Sliver

Diabellstar T.G
Starving Venom Fusion Dragon of the Four Heavenly Dragons Level 8 DARK Dragon Fusion Effect Monster ATK/ 2800 DEF/ 2000 2 DARK monsters on the field This card is always treated as a "Predaplant" card
The Mana Rig, Alquist Proft, Master Sleuth, Nin, the Pain Artist, Tameshi, Reality Architect, and many others can really make use of this discounted double-activation sweet spot
You can chain E-Tele to Gullveig and banish both the monster and the Spell