By pairing it with damage redirect creatures like Stuffy Doll or Brash Taunter, you can turn a board wipe into a player kill
They all are Manaliths, they cost 3, tap for any color of mana, and then I prefer them to Commander's Sphere often since they'll tap for other colors that you don't make in case you Clone, Bribery, Insurrection or otherwise steal things that you want to activate
Shahrazad deliberately drags the game out
If youre running a green toxic/poison themed deck, include Contaminant Grafter for card draw and to place a land onto the battlefield on your every end step as long as your opponent has 3 or more poison counters
Its one of the original cards printed for the game, and it still sees play today because of its efficiency and respectable damage
Repeat this is many times as you want, and you'll eventually have an infinite number of rats who all have fear through Marrow-Gnawer