Both sides of the card prevent opponents from casting anything on your turn (sorry, blue players), and having a 6/6 with reach and trample is neat, too
Since Legends Retold can only be found as Dominaria United Box-Toppers, or in Collector Boosters, the rarity of these cards is somewhat of an unknown
They do come into play attacking and are sacrificed at the next end step, so keep the timing of abilities and effect in mind
Heres an outline: 5-8 removal spells 4-6 card draw spells (including flashback cards) 4-6 payoffs (Sahagin, Shantotto, etc.) 2-3 other creatures (Wyvern, Ice Flan, etc.) 17 lands The deck is fairly simple to put together, and really doesnt want much outside of removal, card draw, and payoffs
In my eyes Moment of Silence is better, but it can be redirected or your opponent could have hexproof or protection, so I still thought it was worth highlighting Festival
It could even be triggered by casting a spell - the spell would say "When you cast this spell, Discover X"