Making Soda With Literally Anything But Soda

Summary
Mark and Ethan use a SodaStream to carbonate various liquids and make a new flavored soda. The items used are as follows: At the end of the video, Evan, one of Unus Annus' crewmembers, suggests to carbonate their urine, much to their dismay.
 * Coffee
 * Apple cider vinegar
 * Milk
 * Condiment Mix consisting of ketchup, mustard, and mayonnaise

Running gags

 * Throughout the video, the SCP model from one of preceding episodes is used as Amy's stand-in, with Mark and Ethan addressing the puppet as if it was a real person.