I've seen that and thinking of trying to craft something similar.
Seems could be simple enough.
Take those 12$ furry spider from any stores, those that you can bend the legs to any position you want.
Remove the stuffing from the body and glue and/or sow the spider body on a jacket or vest for the Corgi.
There, you have a corgi with Four Furry Legs on both sides... The rest is to continue adding extra fur patch to make it creepier. :)
I saw that before...it's still hysterical.