This could get ugly

(This land isn't a spell, it's affected by summoning sickness, and it has ": Add .")

Take an extra turn after this one. At the beginning of that turn's end step, you lose the game.

Creatures don't untap during their controllers' untap steps. Whenever a creature enters, untap all creatures.

All creatures have haste.

Shroud (This enchantment can't be the target of spells or abilities.) : Put X tower counters on this enchantment. At the beginning of your upkeep, if there are 100 or more tower counters on this enchantment, you win the game.

Enchant creature Enchanted creature has ": Create a token that's a copy of this creature, except it has haste. Exile that token at the beginning of the next end step."