Joke SCPs are SCP objects that exist in the game as novelties and comical value, and can be classified as easter eggs. They're technically non-canon with the SCP Foundation.
SCP-420-J, known as "The Best in the World", is a Safe-class joke object that can be found in the head office, which requires a level 4 or higher keycard to enter. Two joints of SCP-420-J can be found on the table in the room along with a document and a readable screen in the room. Entitled "Some SCP-420-J", using the item will cause the file
Mandeville.ogg to play, a slight "blur" when the player moves, and a text to appear at the bottom of the screen saying, "MAN DATS SUM GOOD ASS SHIT", presumably said by the player. If the player is wearing SCP-714, SCP-420-J will have no effect prompting the text to appear as, "DUDE WTF THIS SHIT DOESN'T EVEN WORK". SCP-420-J can also cure the nausea brought on by the strange bottle and heal injuries.
Putting SCP-420-J through SCP-914 will give the player a number of alternates from it, the exact form depending on which setting that SCP-914 is turned to. Putting SCP-914 on "1:1" will result in a cigarette, which will disappear when used and cause a message to appear saying, "I don't have anything to light it with. Umm, what about that... Never mind." Putting it on "Fine" will result in a joint and "Very Fine" will result in a smelly joint, which, if consumed, will kill the player. A message is also shown that reads, "UH WHERE... WHAT WAS I DOING AGAIN... MAN I NEED TO TAKE A NAP...".
SCP-789-J, entitled the "the butt ghost!!" on the Wiki, is a Safe-class joke object. The player can encounter SCP-789-J by entering the WC room. Going near a toilet will cause a sound file to play, saying, "I am the Butt Ghost. I will eat your butt!". It serves no other purpose than comic relief.
The sound that plays when the player goes near a toilet
|SCP Link||Anomalous Ducks|
Another duck can be found when entering the catwalks. It looks similar to the first duck, except for the fact that this duck has a saxophone on its side. When the player is not looking at it, the duck will play a random collection of off-beat notes produced by a saxophone if the player is still in the same room. When the player looks at the duck while it is playing the saxophone, it will stop playing until the player looks away again.
The last duck can be found in the server rooms, where it rotates toward the player after they blink and levitates off the ground for a couple of seconds randomly. This duck is most notable because it is white instead of yellow like the other two.