Devastating Dreams

As an additional cost to cast this spell, discard X cards at random.
Each player sacrifices X lands of their choice. Devastating Dreams deals X damage to each creature.

Thoughts of Ruin

Each player sacrifices a land of their choice for each card in your hand.

Mana Breach

Whenever a player casts a spell, that player returns a land they control to its owner's hand.

Naked Singularity

Cumulative upkeep {3} (At the beginning of your upkeep, put an age counter on this permanent, then sacrifice it unless you pay its upkeep cost for each age counter on it.)
If tapped for mana, Plains produce {R}, Islands produce {G}, Swamps produce {W}, Mountains produce {U}, and Forests produce {B} instead of any other type.