Guardromon halves your own HP in exchange for +300 attack, and he has the Crash effect

Faerie Guidemother Fang Dragon Fang Dragon Fell Horseman Fell Horseman Ferocious Werefox Ferocious Werefox Flaxen Intruder Flaxen Intruder Foulmire Knight Foulmire Knight Frantic Firebolt Frolicking Familiar Frolicking Familiar Galvanic Giant Galvanic Giant Gandalf, Goblins' Bane Garenbrig Carver Garenbrig Carver Garenbrig Squire Ghost Lantern Ghost Lantern Giant Killer Giant Killer Gingerbread Hunter Gingerbread Hunter Glamdring, Foe-hammer Glin the Mighty Gollum, Silent Slinker Gorion, Wise Mentor Grabby Giant Grabby Giant Gray Slaad Gray Slaad Great Ugly-Looking Goblin Guardian Naga Guardian Naga Gumdrop Poisoner Gumdrop Poisoner Heartflame Duelist Heartflame Duelist Hearth Elemental Hearth Elemental Hezrou Hezrou Hildibrand Manderville Hildibrand Manderville Hollow Scavenger Hollow Scavenger Horn of Valhalla Horn of Valhalla Horned Loch-Whale Horned Loch-Whale Howling Galefang Hypnotic Sprite Hypnotic Sprite Illithid Harvester Illithid Harvester Imodane's Recruiter Imodane's Recruiter Intrepid Trufflesnout Intrepid Trufflesnout Ishgard, the Holy See Ishgard, the Holy See James, Wandering Dad James, Wandering Dad Jidoor, Aristocratic Capital Jidoor, Aristocratic Capital Karvanista, Loyal Lupari Karvanista, Loyal Lupari Keeper of the Crown (adventurer)(playtest) Kellan, Daring Traveler

Yes, you must reveal a cloaked creature any time it would leave the battlefield, and at the end of a game
This gives you a real-time snapshot of its current market value, not just what sellers are hoping to get for it
This is because there's another Booster Fun version of Okoa borderless versionand in general, our heuristic is to maintain the relative ratios of "Booster Fun versions of Oko" with "Booster Fun versions of other mythic rares." This means that if a card has multiple Booster Fun treatments, you're less likely to open any particular version, but you're just as likely to open a Booster Fun version of Oko as any other card overall