Drawback 4: Dungeon Descent requires you to tap an untapped legendary creature you control in order to activate
In Cube, the effect is also good but the cost and sorcery speed will keep it from the big leagues

$39.99 Knight of the Reliquary Time Spiral Remastered $54.99 Dryad of the Ilysian Grove (191 - Foil) Secret Lair $11.99 Entish Restoration (0614 - Scroll Showcase - Silver Foil) The Lord of the Rings: Tales of Middle-earth Variants $69.99 Bolas's Citadel (0007 - Kefka's Tower) Final Fantasy Through the Ages $34.99 Jodah, the Unifier (0017 - Warrior of Light) Final Fantasy Through the Ages $29.99 Command Beacon (0064 - Balamb Garden) Final Fantasy Through the Ages $32.99 Sram, Senior Edificer (0003 - Firion, Swordmaster) Final Fantasy Through the Ages $4.99 Dovin's Veto (0051 - Shadowbringers) Final Fantasy Through the Ages $37.99 Gix, Yawgmoth Praetor (0035 - The Shadow Lord) Final Fantasy Through the Ages $14.99 Teferi, Mage of Zhalfir (0032 - Edea Kramer) Final Fantasy Through the Ages $49.99 Loran of the Third Path (0024 - Garnet Til Alexandros 17th) Final Fantasy Through the Ages $32.99 Chromatic Lantern (0061 - Crystal of Altar Cave) Final Fantasy Through the Ages 0 results found

This is most prominently represented by Santa's sleigh pulled by the reindeer, but also traditional sleigh rides that normal people can use too
Now you can see how your deck is really going to play
Bruvac the Grandiloquent is one of the best mill-related cards in all of Magic: The Gathering, and hes finally seeing a main set reprint in the upcoming Ravnica Remastered