TNT posted this in the editorial today:
**Community Notice**
We discovered a glitch this morning with the new avatar, which was causing it to be granted in ways that were not intended. If you got it already, no reason to worry or write in, but we have also fixed the glitch so it will no longer be given out in this unintended manner.
So apparently since it was being given randomly when depositing items into your SDB this was a glitch.
Currently the word is if you DISCARD,
not deposit, the items specifically shown in the avatar in a specific order, the "steps" TNT mentioned, then you get the avatar.

Tin Can and Rotten Berry from the looks of it is all you need to discard. However it doesn't seem to just work that easily either. I personally don't think that the solution has been found quite yet.