This is Rumble cosplaying as Stan Marsh from South Park.
 
Rumble belongs to Hasbro and DHX Media
 
Stan Marsh and South Park belong to Comedy Central
 
Rumble vector by Chrzanek97
 
Up Next:
 
Tender Taps as Kyle Broflovski  
Snips as Eric Cartman  
Featherweight as Kenny McCormick  
Shady Daze as Craig Tucker  
Chipcutter as Butters Stotch  
Pipsqueak as Tweek Tweak  
First Base as Token Black  
Carrot Crunch as Jimmy Valmer  
Skeedaddle as Kevin Stoley  
Button Mash as Clyde Donovan  
Sweetie Belle as Wendy Testaburger  
Scootaloo as Jenny Simmons  
Apple Bloom as Red