What makes Otrimi, The Ever-Playful great is when it deals combat damage to a player, you can return a creature with mutate from your graveyard to your hand
(1) Take 1 Rank-Up-Magic The Seventh One, 1 Seven Emperors Spell/Trap other than Ascension of the Seven Emperors, 1 Barians Spell/Trap, or 1 Rank-Up-Magic Quick-Play Spell from your Deck, and either add it to your hand or place it on the top of the Deck
These sleeves from Ultra Pro show off the splendor of Bloomburrow, thanks to an illustration by Carlos Palma Cruchaga
I built around her long ago for a Budget Commander
You basically cant attack into it, for risk of flipping your opponent into whats likely to be their best card, though you cant always stop them from feeding the Rector to a sacrifice outlet