How to Build: Lego Unicorn Instructions--9 ways! Lego Unicorns are the best! I found a severe lack of Unicorn Lego instructions and decided to make my own. Build the most epic Lego Unicorn with a rainbow colored mane, gold tiara and horn, rainbow colored waterfall tail and star cutie mark on the flank! Full PDF instructions for this Lego Unicorn in the supplies list below! I absolutely love Lego and I love Unicorns, so I decided to combine the 2. I spread out a blanket on the floor and dumped the 2 giant totes of Lego pieces on it one morning. I told my 9 year old son (he's 14 now) that I needed to build a Lego Unicorn...but I had to go to the gym first. When I got back, he had already put together a darling little unicorn. I sat down with him and we created 9 different unicorns, all uniquely adorable in their own way. Here's a fun set that Lego sells with a Unicorn ...it's got wings, so it's actually an Alicorn! But would you believe