Scapeshift is one of those decks at the fringes of Modern. It pokes its head out when the format doesn't have a lot of fast combo and instead has decks with disruption it can fight through. Unfortunately, Grixis Death's Shadow might have a little bit too much disruption, with eight discard spells and Stubborn Denial to go along with a very fast clock.
So, in an effort to combat the new boogeyman, today's Scapeshift list is a whole lot more interactive, hoping to use the threat-light nature of the Death's Shadow decks against them to buy lots of time and power through their disruption simply by getting more draw steps to find what they need.
There are the typical eight ramp spells in Search for Tomorrow and Sakura-Tribe Elder but only a singleton Cultivate on top of them, which is a tutor target for Dark Petition. Instead the deck features a whopping thirteen removal spells and a singleton Liliana of the Veil. That's almost as many total threats as most Death's Shadow decks have, so you should be able to keep the battlefield clear so long as you're judicious in your use of Terminate.
Once you do that, you have plenty of time to make land drops and find a Scapeshift, and the addition of four copies of Dark Petition gives the deck an added layer of redundancy a la the Bring to Light lists. Petition is a great card for this deck given how easy it is to turn on Spell Mastery, to the point where I'm surprised not to see more of a toolbox in the maindeck.
Singleton threats like Primeval Titan or one of the Grave Titans in the sideboard could slide their way into the maindeck, as could more versatile removal spells like Maelstrom Pulse. There's a lot of flexibility there, and while I'm not a fan of going overboard with toolboxes, I think this one is under-equipped.
Regardless, I love the addition of Dark Petition over Bring to Light, which has more restrictions and stretches your manabase. Scapeshift has always been a deck that had the space to fit in plenty of interaction, but there's no law saying that interaction has to be blue.