The Forgotten Cellar half is very expensive for what it is, but its still a great bonus on top, especially if you can ramp using the left half
For better or worse, this has the potential to be a game-changer as the Adventures can theoretically provide some amazing late-game value
It certainly looks powerful when you transform it, but costing 7 mana to do so really holds it back
In Modern, this already lines up very well against Ragavan, Nimble Pilferer, and can ping down mana dorks, Esper Sentinel, and more
I wish I had a Predator Ooze in my starting collection (and you can, with the Foundations Starter Collection!)
5 Add: Crystal Barricade Cut: Nyx-Fleece Ram Swapping one two mana creature out for another makes for an easy exchange, but with Crystal Barricade, you get a much better deal out of it