THIS IS TAKEN FROM KNOWYOURMEME
WaterGuy12 is a Redditor who gained much notoreity on the r/me_irl subreddit after asking Redditors to comment his username on posts featuring “good memes” while he was without an internet connection from late July to mid-August 2017. The post subsequently started a war between supporters of WaterGuy12 and an account named FireGuy12. In June 2019, WaterGuy12 announced a second trip, prompting a second wave of memes.
On July 29th, 2017, WaterGuy12 posted on the r/me_irl subreddit, where he talks about how he is going to a place without WiFi for two weeks (until August 14th), and asked the people of the sub reddit to tag him on any good memes so that he “doesn’t miss out”. In the following 6 days, the post accumulated over 9,000 upvotes.
On August 5th, user martinber123 posted to r/OutOfTheLoop, asking “Why is everyone tagging u/waterguy12 in every comment” .
Over the next five days, users of the me_irl subreddit tagged WaterGuy12 in almost every single post on it. Some even created bots to help them tag WaterGuy12 in every post.
On August 4th, 2017, a user by the name of FireGuy12 submitted a post to the subreddit, claiming that the user would set the subreddit ablaze if people did not give him upvotes  . The post accumulated over 11,000 upvotes over the course of the next 24 hours.
On the next day, FireGuy12 made another post requesting more upvotes in exchange for not setting the subreddit ablaze. FireGuy’s posted started a barrage of posts from various users, who began siding with either WaterĢuy12 or FireGuy12.
Along with that, many different accounts were created, with every username being simply some item followed by “Guy12”. These users began posting images, asking users of the subreddit for upvotes in exchange for some action or event happening (usually involving the defeat of FireGuy12). Many users began posting other images referencing the war between FireGuy and WaterGuy. Along with that, many jokes appeared in the comments of images related the war.
On August 14th, WaterGuy12 posted an image to the /r/me_irl, stating that he was reading the responses while riding on a train and expressing surprise at how he became a meme. He also said that he has over 3,200+ notifications that kept glitching out and that he has “a few things planned” for when he comes home. Within six hours, the post gained over 59,000 votes (85% upvoted) and 6,000 comments.
Shortly after, FireGuy12 submitted a post responding to WaterGuy12 on /r/me_irl, where he threatened to burn the subreddit “to the ground” (shown below). The post accumulated over 9,000 votes (76% upvoted) and 650 comments within six hours.
In the comments for FireGuy12’s post, WaterGuy12 responded by teasing FireGuy12, triggering a humorous exchange between the two accounts filled with water and fire emojis (shown below).
On the same day, WaterGuy posted on the r/waterguy12 subreddit, asking them to raid the r/fireguy12 sub with images of water. The post accumulated over 33,000 up votes, and the r/fireguy12 subreddit got filled with images of water. 
A few hours later, FireGuy12 posted on the me_irl sub reddit, begging WaterGuy to stop killing him, and asking for a truce “for their old friend Fernando”.  The post accumulated over 4,000 up votes, and WaterGuy12 agreed to stop the fight. On the same day, he also posted on the r/waterguy12 subreddit, announcing ceasefire and their truce.
On the same day, WaterGuy posted on the me_irl subreddit, showing that he has over 60,000 notifications.
WaterGuy12’s 2019 Trip
On June 28th, 2019, WaterGuy12 announced that he would be making another trip without access to the internet between June 30th and July 15th, 2019, asking /r/me_irl subscribers to “tag him in all of it” (shown below, left). The post gained over 52,600 upvotes in three days. On June 30th, WaterGuy12 posted made another post notifying of his departure, gaining over 9,500 upvotes in one day (shown below, right).
In the following days, multiples posts referencing about WaterGuy12 were posted in /r/me_irl. Many notable posts in the subreddit, as well as in other meme communities, were tagged with the WaterGuy12’s username.
On June 29th, 2019, Redditor TheMewZe made a post featuring Polar Bear GIF”:https://knowyourmeme.com/memes/polar-bear-gif (shown below, left), supposedly inspired by the WaterGuy12’s message to “show newcomers one of [/r/me_irl]’s greatest sagas. In the following days, more older memes once popular in the community were posted, most notably Dat Boi (shown below, center and right).
On June 29th, following the WaterGuy12’s departure announcement, FireGuy12 made a post which gained over 16,300 upvotes in two days. In the following days, FireGuy12 made more posts revealing malicious plans for the period WaterGuy12 would be missing.