This is a nice board changer at a very acceptable price
You might think about all the card draw or value spells you can duplicate, like Ponder, Preordain, or Dig Through Time
Whether its due to an excellent illustration, competitive potential, a deep amount of nostalgia or some other factor, it can be confusing to figure out which cards are best in Obsidian Flames
It's both an Eldrazi and an Octopus, so it plays into both your big creature groups, you can sacrifice another creature to make it cheaper (and thus have a target in your graveyard to reanimate later), and has Flash, so you can tap down four permanents whenever you cast it
In the TMNT sets ecosystem, this is huge
If the ninjutsu ability had been introduced in a different set, with different flavor and on different creatures, I wonder if it would have become another recurring mechanic, like cycling or convoke