Shopkeeper

Shopkeepers are present in every Shop and most Secret Rooms, and can also be found in Vaults, Arcades, Bedrooms, and I AM ERROR rooms. They cannot be hit by normal attacks, but explosions and certain items will damage them. Occasionally, destroying them will yield rewards. Destroying a shopkeeper increases the chance for a Devil Room or Angel Room to appear by 10% for the current floor.

• The Shopkeeper's faces occasionally take on the appearance of certain popular Internet memes, such as "Forever Alone".
• A Shopkeeper shares the appearance of a Dummy.
• Edmund has confirmed that all Shopkeepers (and, by extension, the Keeper) are mummified versions of Isaac from previous runs.[1]