As a land it cannot be countered, and its ability is always available for use
The obvious downside is that it can only copy your own things, but given the rest of the card, thats hardly a downside at all
Put one of them into your hand, and the rest on the bottom of your library in random order
Most of us Magic: the Gathering players began our collections with a fairly random assortment of cards, a mix of the most current booster packs plus some donated cards from other players collections
Instead of Cocoon, try Forced Adaptation, which puts a +1/+1 counter on the enchanted creature each turn without a drawback, or Spider Umbra, which gives your creature +1/+1 and reach, plus is a Totem Armor
Its not a huge surprise to see both Urza and Mishra in card form here, and its also not a huge surprise to see them as some of the more powerful cards in the set