Puppycorn originally had a light blue horn with a purple base. His paws were originally meant to be navy topped with white as well, while his color scheme was a navy color, rather than the bright blue it is now.
Carrying over from The LEGO Movie, Unikitty's body can change dramatically in ways that should not be possible. The same applies to Puppycorn, having a body similar to his sister's.
Although the official premiere date for the series is January 1st, 2018, 3 sneak peeks for the series premiered first in late 2017; October 27th, November 17th, and December 1st respectively.
The plot for "Spoooooky Game" is very similar to "Game Night" from Vampirina, in that they both follow plots on supernatural board games. They even aired on the same day.
Puppycorn was originally colored a darker blue, with navy paws instead of red, and a blue horn with a purple holder instead of a yellow horn with a red holder.