mtg unstable cards Magic Word [Unstable] some skin. Unstable Experiment | Marvel's Spider-Man

With so many locations allowing you to move to them for just one ink, this essentially makes those locations free to visit

All in all, it's not impossible that Cabal Stronghold shows up in a Mono-Black Control list in Standard, possibly using Torment of Hailfire and some big Demons like Razaketh, the Foulblooded and Demonlord Belzenlok as finishers

a mana rock that reduces your clock by a turn or two is well worth the three-mana investment

Many of the games we lost were due to not hitting our lands on time

Can I use these printed cards in sanctioned tournaments

Yes, it will benefit your other opponents similarly to the C17 curse cycle (Curse of Opulence, Curse of Disturbance, etc.), but it will also incentivize those opponents to send more Creatures towards the cursed player to benefit from the free card advantage (and additional damage thanks to Trample)