In the bowl of a stand mixer mix the butter and the powdered sugar, beat until blended, then add salt, mix.
Add milk and vanilla and beat until smooth and creamy, about another 3-5 minutes.
Once cake is completely cooled place one layer on a plate or a round cake board, spread with some of the white butter cream.
Add the second layer of cake.
Then frost the entire cake with a very thin layer of frosting.
Place in the refrigerator for 20 minutes.
In the meantime, place a flat decorating tip (if you do not have a flat tip the one that makes rose petals is fine too) inside a cake decorating bag and then fill with frosting.
Cut off the tip of the bag.
Now make "bandages" with the frosting. I went around the cake and then did the top. The good news is that it's frosting, if you do not like how it looks scrape it off and start again.
Once you have your bandages, add the cookies and the brown M&Ms for the eyes.
Then slice and enjoy!