They each ramp any land untapped - no sacrifices or anything else - just get what is needed for that situation
Once per turn: You can target 1 face-up banished "Toon" card
I first saw it and thought of all the ways I want to take advantage of it, and now I find myself upgrading the Mardu Surge precon
Valakut, the Molten Pinnacle's triggered ability has an "intervening 'if' clause." That means (1) the ability won't trigger at all unless, at the time a Mountain enters under your control, you control five or more Mountains other than that new one, and (2) the ability will do nothing if you control fewer than five Mountains other than that new one by the time it resolves
Ghost jokes aside, this pairing has been pulling its weight, as it continues to climb from its starting point in the $90s, and has continued to skyrocket up past the $120 mark
There are plenty of amazing Un-cards to add to your Cube and these are some of the best