Unicorn Chomper Question

If you have, or acquire, Garden Warfare 1 and then grind your way through it until you hit Rank 313 you will be able to use the mailbox in Garden Warfare 2 to check your GW1 rank, at which point the game will award you with a special sticker pack containing the Unicorn Chomper and his special Rainbow Warp ability.

If you start from scratch in GW1 and play the game towards doing the Star Quests which are required for ranking up and you spend your Skip Challenge Stars on the stuff which requires huge amounts of luck or which is just down right crazy time consuming you can hit Rank 313 in about 225 hours as a minimum. Make no mistake; it's a grind and you'll probably come to hate the game since hitting those challenges means that you have to play a certain way sometimes with certain characters and you'll need to play all of the character classes up to their maximum rank of 40.

Bear in mind you need to do this before February of 2017, which gives you about 6 months. After February they have stated that the character/rank importing feature will be ended.