What a confusing set of abilities. There doesn't seem to be any relationship between the different effects.

Is Boundary supposed to be granted to the creature that's equipped? I ask because the reminder text says creature, even though this is an artifact.

I think this needs to be reworded more like the following:

Equip X

When you equip ~, put X (counters) on ~ equal to ~'s equip cost. Equipped creature gets +0/+X equal to the number of (counters) on ~, and has Boundary.

If ~ is not equipped to a creature remove all (counters) from it.

Also, some what weak as a mythic.

Yowsers. draw X cards. AND repeatably? Scary powerful. And adds life just for random "You really cannot stop me".

It's a better Braingeyser, it's not blue, it recurs. It's just way too good. Why wouldn't I splash four of this into every deck? Even if I can't recur it?

And the name suggests it ought to have the Miracle ability; which thankfully it doesn't.

It's Sphinx's Revelation, except with buyback ...

I'm still upset that nobody's put a clip of Mel Gibson shouting "It's a Miracle!" from History of the World: Part I on Youtube. I'd be linking to that thing all day long.

Its better then Sphinx's Revelation, its mono white! And you can pay back the buyback latter for larger retrun now!

Though it is sorcery speed...

This is like...a Ultra-Mythic Super Rare

When do the instructions happen? When you cast it or when it ETBs?

you mean Mel Brooks.

Ha! I certainly do. Though, I'll also take Mel Gibson shouting "It's a Miracle!".