Can a spell that says 'target creature you don't control' target a creature with shroud your opponent controls?

Shroud is a static ability that makes a permanent (or player) an illegal target for any spell or ability. This applies universally — it doesn't matter whether the spell is controlled by the creature's owner, an opponent, or anyone else. CR 702.11b states that 'a permanent or player with shroud can't be the target of spells or abilities.'

When you cast a spell and choose targets, you must choose a legal target that meets all criteria (CR 601.2c). A creature with shroud fails the targeting legality check entirely, so even though the creature is one you don't control — satisfying that part of the spell's text — shroud makes it an illegal target regardless.

This is different from hexproof, which only protects from spells and abilities controlled by opponents. Shroud is symmetrical and blocks targeting by everyone, including the creature's own controller.

Example: Your opponent's Asceticism gives their Grizzly Bears shroud. You cast Pacifism, which says 'enchant creature you don't control.' Even though the Bears are controlled by your opponent, you cannot target them with Pacifism because shroud makes them an illegal target for any spell.

If at any point shroud is removed from the creature (e.g., via Glamerdye or the ability being turned off), it would again become a legal target for your spell, assuming it still meets the other targeting requirements.