At the beginning of combat on your turn, if you control two or more other legendary creatures, you may transform Serah Farron
it turns your least significant creature into a very scary card, though it costs a whopping 8 mana to do so and it cant even attack the turn you flip it

$32.99 Nyxbloom Ancient (0016 - The Cloudsea Djinn) Final Fantasy Through the Ages $57.99 Ranger-Captain of Eos (0002 - Knights of San d'Oria) Final Fantasy Through the Ages $5.99 Gix, Yawgmoth Praetor (0035 - The Shadow Lord) Final Fantasy Through the Ages $32.99 Urza, Lord High Artificer (0005 - Terra Branford) Final Fantasy Through the Ages $9.49 Cryptic Command (0029 - To the Crystal Tower) Final Fantasy Through the Ages $9.99 Chromatic Lantern (0061 - Crystal of Altar Cave) Final Fantasy Through the Ages $8.49 Loran of the Third Path (0024 - Garnet Til Alexandros 17th) Final Fantasy Through the Ages $39.99 Purphoros, God of the Forge (0014 - Kefka Palazzo) Final Fantasy Through the Ages $3.49 Kraum, Ludevic's Opus (0056 - Barnabas Tharmr) Final Fantasy Through the Ages $57.99 Ragavan, Nimble Pilferer (0043 - Zidane Tribal) Final Fantasy Through the Ages $32.99 Yawgmoth, Thran Physician (0011 - The Emperor, Hell Tyrant) Final Fantasy Through the Ages $39.99 Atraxa, Grand Unifier (0049 - Sephiroth, the Savior) Final Fantasy Through the Ages 0 results found

4 mana is such a high cost that you guarantee players with either hold their spells (which is extremely good for you), or they feed you boatloads of cards
As another example, if my opening hand has a one-drop, a two-drop, a three-drop and four different four-drops, then I will usually bottom the worst three four-drops in the hope of drawing into a powerful five or six-drop, while keeping the cards that will ensure a perfect 1-2-3-4 curve-out