Grug is the name, associated with a caveman design of Wojak.
The character is usually depicted as talking in grunts and simple words, similar to the superhero Hulk.
The name “Grug” originates from the 2013 DreamWorks animation, The Croods.
It is the name given to the overly protective and cautious father of the Croods; Grug Crood (dubbed by Nicholas Cage).
“Grug” started emerging online in 2014, as several 4chan users on the /tg/ board started posting greentext stories, roleplaying as cavemen.
The earliest depiction of “Grug” similar to the modern Wojak design first emerged on 4chan in October, 2017.
It spread on to Reddit by November, 2017, appearing on the r/2007scape subreddit.
Since 2017, the character design of “Grug” evolved into a caveman rendering of Wojak, appearing on comics, image macros as well as YouTube videos.