

I guess if you want a plant that would be fair game.
In that case, I would choose a quaking aspen based on the specimen named Pando. I would have a vast array of sizes at my disposal, from as small as a single seed to as large as the 106 acres that Pando covers.
I want to escape from somewhere? Turn into a seed. I want to destroy an environment? Turn into a giant network of trees.

Also works for haunted plastic dolls