The most recent Gold Puffin animation contest was held in February and March 2019. The theme was Heroes, and there were 113 entries, mostly brickfilms but including other kinds of stop motion as well.
The next Stop Motion Contest is likely to be hosted if and when Gold Puffin reaches 10,000 subscribers. Subscribe to Gold Puffin on YouTube and hit the notification bell to make sure you don't miss the announcement when the contest starts.
Stop Motion Contest
There have been two MOC ('My Own Creation') contests on Gold Puffin so far. There may be more MOC contests in future, but no dates have been set for any yet.