UBR is a spell-heavy control/midrange deck full of cantrips and counterspells (Deduce, Make Disappear, Negate), so Magebane Lizard punishes their card selection while its 4 toughness survives Fiery Impulse. Scorching Shot's 5 damage is needed to kill their bigger threats off Indomitable Creativity or Fable of the Mirror-Breaker tokens, and can reach Fable's token copies. Monstrous Rage and Kumano Faces Kakkazan are cut since they're vulnerable to Fiery Impulse and counterspells without enough payoff against a grindier opponent. Play around Make Disappear and hold extra gas since they have real card advantage engines (Fable of the Mirror-Breaker, The Theorist, Jace Beleren) if the game goes long.