msem-instigator

As an additional cost to cast this spell, exile a noncreature artifact you control with mana value X until Barx leaves the battlefield or fails to resolve. X can't be 0.
[+1]: Exile the top card of your library. You may play it until you exile another card with Barx.
[–3]: Create an X/X colorless Hound artifact creature token, where X is the greatest mana value among cards exiled by Barx.
[–10]: Search each player's library for any number of nonland cards with total mana value 10 or less and exile them, then those players shuffle. Cast those cards without paying their mana costs.