So, I thought I had hexproof down pat. However, I'm now slightly confused. Can I enchant a creature with hexproof that I don't control? Being as I'm not targeting it? Doesn't that mean hexproof only really protects from instants and sorceries?
If so that means hexproof isn't half as good as I thought it was.
To enchant something you must target it. Aura type enchantments have an understood "target" in them.
Edit with ruling:
114.1b (http://imtgapp.com/forum/index.php?action=imtg;area=rule;number=114.1b): Aura spells are always targeted. These are the only permanent spells with targets. An Aura's target is specified by its enchant keyword ability (see rule 702.5, "Enchant"). The target(s) are chosen as the spell is cast; see rule 601.2c. An Aura permanent doesn't target anything; only the spell is targeted. (An activated or triggered ability of an Aura permanent can also be targeted.)
The way that people bypass Hexproof with Auras is by putting them straight on to the battlefield without casting them. When you place an Aura on to the battlefield (via {Zur the Enchanter} or {Sun Titan} with something like {Pacifism}), you simply choose a legal object to attach to. Since Hexproof and Shroud only care about targeting, you're not targeting them. Since you're not targeting, they're legal choices.
The same can be said for {Prison Term} once it's on the battlefield. If a creature with hexproof or shroud enter the battlefield you can attach it to then directly.
Okay sweet. Thanks guys.