Custom cards are not legal for sanctioned tournament play
You might have noticed that this card has a lot in common with Sun Titan
In a similar vein, "buttbreathing" or "butt-pumping" is an ability that spends mana to pump the creature's toughness, such as Mesa Falcon and Armor Sliver, due to a creature's toughness being colloquially known as its "butt" (as noted above)
Assert Authority Blinkmoth Infusion Broodstar Chiss-Goria, Forge Tyrant Chromescale Drake Demonic Junker Don & Raph, Hard Science Emry, Lurker of the Loch Ethersworn Sphinx Frogmite Frogmyr Enforcer Furnace Dragon Furnace Hellkite Gearseeker Serpent Icebreaker Kraken Imskir Iron-Eater Into Thin Air Krang, Master Mind Lens Flare Memory Guardian Mycosynth Golem Myr Enforcer Panther Robot Plated Onslaught Quicksilver Behemoth Qumulox Reality Heist Refurbished Familiar Saheeli, the Gifted Sami, Wildcat Captain Scale of Chiss-Goria Slag Strider Sojourner's Companion Somber Hoverguard Steelfin Whale Tezzeret, Master of the Bridge Thought Monitor Thoughtcast Tooth of Chiss-Goria Utrom Monitor Valkyrie Aerial Unit Voyage Home
This includes face-down creature spells cast with morph's alternative cost
