Kinectimals

After completing Fort Topaz and Kokopo Cave, finding the Super Plunder Scope, traveling and playing contests in every area of both Lemuira and Mira, you discover the new and last area of Mira. This is where you'll compete in the 4 round volcano contest. Once you have completed the contest you'll discover your new friend and unlock an achievement.

NOTE: I am unsure if you need to gold this event, or if just completing it is enough. However, it was quite easy to gold with only a total of 25,000 points needed. I was able to gain around 36,000 points on my first attempt. I will update this solution after I check on other profiles.

After getting the above achievement, this will be the next achievement you get.

Once you've passed all the cutscenes and such, you'll have to do a four-round contest.
Round 1 involves you helping your bear cub climb up and down a totem pole, pressing buttons around it at various heights. I completed this round with 12,000 points with 1 second remaining.
Round 2 involves you throwing disks against skittles for points.
Round 3 is the same as Round 1, but a little shorter than Round 1. I completed this round with 10,500 points with 4 seconds remaining.
Round 4 is the same as Round 2, but you have more targets than in Round 2.
Assuming you manage to get perfect points from Rounds 1 and 3, you can have a really horrible aim in Rounds 2 and 4, and still get the gold medal, which will unlock your new friend. And it's a VERY nice friend too <3

Enjoy your new friend, and your 50G achievement!