This deck is obviously just for fun.
However I like winning too, so over the past couple of days I kept perfecting it and it's actually become a pretty competitive deck. Nevertheless I don't think I need to tell you that this isn't tier 1.

Objective

This is a control-ish deck. You survive, draw and play as many Underworld Dreams as possible. 
Then you start copying your Dreams with Mirrormade. 
Then you go back to surviving and just wait and let your Dreams pew pew your opponent to death.

This strategy isn't always viable though, that's why I based this deck around enchantments and not just Underworld Dreams.
So if you can't pull off the "dream" combo of getting 8 Dreams on the board, start copying other enchantments with your Mirrormade.

Card Purpose

• Mirrormade
  You use this primarily to copy Underworld Dreams, but like I've said before, it doesn't always work. However there are plenty of other enchantments in the deck so you can copy other stuff too. Copying Doom Foretold for example is also very powerful.
  
  
• Golden Egg
  Great card draw, can fix your mana and the potential lifegain is definitely relevant against aggro or midrange decks.
  
  
• Oath of Kaya
  Good removal and it's a target for Doom Foretold.
  
  
• Treacherous Blessing
  Incredible card draw and the perfect target for Doom Foretold.
  
  
• The Birth of Meletis
  It's another form of "card draw" that can also fix your land problem. It's also another enchantment and the blocker plus the life gain are great for survival, which is of utmost importance for this deck.
  
  
• Shatter the Sky
  This is a great sweeper. And the fact that it lets your opponent draw a card (sometimes) is actually a good thing! Because it means your Underworld Dreams will do more damage.
  
  
• Doom Foretold
  Great for removing annoying permanents and it gets rid of your Treacherous Blessing.

Tips

• Make sure you never have more than 1 Treacherous Blessing on the board.
  If you have 2 or more you kill yourself real quick. 
  The only time you could have more than 1 is when you also have a Doom Foretold on the board.
  
  
• Doom Foretold can be a great target for Mirrormade.
  
  
• Don't just use Mirrormade for your Dreams. There are other enchantments you can copy.
  
  
• Don't try to play Underworld Dreams too quickly. Especially versus aggro you're supposed to stabilize first.

Sideboard

• Dovin's Veto is mostly for when you're up against a counter deck. Use this to protect your Underworld Dreams or a Doom Foretold
  
  
• Despark is obviously for against midrange or control when you need more removal. 
  
  
• Tyrant's Scorn is for when you really need more cheap removal in an aggro matchup.
  
  
• Emergency Powers
  This card actually has amazing synergy with Underworld Dreams, but I didn't put it in the main deck because it's a little bit too clunky. But this card instantly wins you the game if you're against mill.
  
  
• Ashiok, Nightmare Muse
  Just a great value card that's pretty good in the current standard meta right now.

Underworld Dreams is a really fun card so I tried to make something work with it.
I hope you enjoy the deck.

Cheers.