All the People is the name of three small ball-type creatures who each represent a different emotion - sadness, anger, and happeiness - and as a whole they represent large swathes of people whenever I didn't want to draw them. All the People are usually drawn with many copies of themselves to portray many thousands of people. In their informative page in Slime Uprising Part 1, it's said that "these people multiply every day". They are also "funny".
The three obviously have personalities matching their facially-fixed emotion. The angry one sometimes is known to help Joe Turtle in his schemes against Willy Sketch.
All the People appear in Willy and Rob's Issue #7, in the second issue of The Pac Chronicles as getting armor in the Armory 1.0, assumably to fight the Ghosts. They are never seen doing any such thing.
All the People on a robot rat dressed up like a rat is the PERFECT variation of the 3-headed ratt from the Nutcracker.
All the ratt king's minions (also all the people).