Collapsing Bubble / Expanding Bubble

Collapsing Bubble 1UU
enchantment
Collapsing Bubble enters the battlefield with X force counters on it, where X is the number of islands you control
At the beginning of your upkeep, remove a force counter from collapsing bubble. If you can't, sacrifice it.
Opponents may not play spells with converted mana cost greater then X, where X is the number of force counters on collapsing bubble

Expanding Bubble 1UU
enchantment
At the beginning of your upkeep, add a force counter to expanding bubble.
Opponents may not play spells with converted mana cost less then X, where X is the number of force counters on collapsing bubble

Well for this to work you would need to have both in a deck, and if you play them its kinda harsh... and unfair. And it would be more logical for them to be artifacts.
Like all of THESE.