Before I give this card the rightfully-deserved thrashing I'm about to give it, I need to mention the two good things about this card. First, it replaces itself which is always good. Second, it's soft removal, so it does lock down a creature without actually killing it meaning that it won't trigger any Morbid-type thingies. Now, on to the thrashing.
The first thing wrong with this card is its mana cost. This effect should never cost 6, not even in blue. At best, since it replaces itself, this should cost 4. Secondly, this should at least tap the thing it's targeting since, you know, it's kind of useless to make something stay tapped if it doesn't start tapped. Finally, I personally think that this should be a flat Enchant Permanent instead of just Enchant Creature. For 6 (ideally 4), I would hope you're getting something a little more powerful than a worse Bonds of Quicksilver (which is already pretty bad).
Pros: Replaces itself, soft removal
Cons: Costs 6, doesn't tap the creature