I tried to say "sorry for ks" because I had just came to gank and then took the final shot after my ally had done all the damage but I accidentally put a "d" isn't of an "f" and I failed the space which ment I actually said "sorry dorks"
Probably not my meanest accidental thing but nevermind.
Was playing a tank, and accidentally clicked on 
's lantern.
ADC didn't last a nanosecond.
Sometimes I type things in chat (Just to vent) that I never ever want to send and I accidentally hit enter. Mean words don't make wins.
I accidentally mis-typed "thk u" to "fk u" in in-game chat once.
Although it really wasn't intentional nor did I understand why I even typed that, but yer as you could imagine, it didn't end up all that well as I was trying to justify it as a typo.
At least the guy wasn't mad he was just curious on how I could even mistype the former into the latter, because I am fundamentally a douchebag I guess, it's in my genes.
Me 
trying to wall fed ulting 
from my squishys. I may have saved myself and gave 3 kills away. Man that abilitys hard to cast right with low fps
Sorry for accidentally stealing the baron from enemy team.
"Accidentaly" ran into my bot lanes opponents 15 times. I mean my adc toxicity at 5 mins blinded my champ. I didnt know where i was running.
While playing in Aram 2 years ago....It sure was hella funny but so trolly. If I had Lee Sin, I would kick the enemy away if they were so low and about to die. Sometimes I kicked the enemy towards my super low health teammate.
I really had no clue what I was doing! I never payed attention to health. I kept forgetting I could kick.
Pressed random in URF and got Sona
Saw my brother get a quad kill then wondered why he didn't get a penta kill. As he killed everyone on the team one of them just had ga and got killed by someone else. Checked the match history after the match and saw that I stole it. T_T to this day I am still sorry. Tldr: Stole my brothers penta.
There's a running joke on my team that we always deny our ADC pentas. I've been responsible for 2 denials, personally.
I accidentally stole a penta from a Singed as Veigar in a ranked game.
I didn't even think, I just ulted to secure the kill. Felt so bad afterwards.
As 
a few games ago, our mid laner was being a toxic jerk all game.
And when he got 3v1 ganked, I did not ult just because he was being a huge annoyance. Hint, be nice and you'll get me to save your ***. (In ranked I would have ulted), but it was a normal so it was me trying to teach him a lesson.
Well I stole Drake as Bard support. That felt dirty...
I bought 
when he was op.
I actually refunded him.
When 
steals a kill from me near the gromp, I decided to hit the gromp to kill her
-Playing Aram-
: "Blah-blah-bitching at me since beginning of game for a ks or something"
: "Look how much I care, i'm fucking Gnar." ( I really love getting my main)
HAS SLAIN AN ENEMY- "Yeyy~"
-
Got A Quadrakill!- "Oh..darn it."
(Brain Registers this situation as "Oh, ez must of missed the last guy and he got away)
"Gnar. What the hell? Stealer."
"Whatever"
---While Nexus is blowing up mind instantly realizes that I stole Ez's penta on accident then acted like a total douchebag after I did.-
- Instantly Leaves Post-Game Screen-
"Ez, sorry for ste-.....FU-"
(Spends The Rest Of The Day Feeling Like An Asshole)I lmfa'd.
But probably stealing a penta. I mean, everyone's done that from time to time in the heat of the moment.
I stole my adc's 9th kill of the game
and they afk'd as an 8/0/1 adc
OH MY I MADE BIG MISTAKE
In all seriousness i was playing with my friends and my friends was running from the enemy team so I 
troll pole'd him into the enemy team.
I'm such a nice person
Kept killing an 
whenever she showed her face on the map with 
...The swearing was very scary...
I was 
and ulted the enemy nearly killing her. My ult ended up hitting the krugs and they killed my teams 
who was backing near them.
Also i once pull the enemy 
under my tower as 
and he dies, uses his passive and kills my adc 
I've done some mean things I'm not proud of. Then I did these things, which are mean but I am proud of. Not quite on topic though since none of them were accidents.
Once had a mid-laner that I accidentally KS'd as the support. He flew off the handle about me KSing him, so I proceeded to stalk him for the rest of the game trying to steal his kills. That's not the mean part. The mean part is me convincing our ADC and top-laner to do it too. The game lasted another 20 minutes and our angry mid-laner got every single kill stolen from him by one of us.
I once watched a player in a bot game who had been especially obnoxious and rude all game sit back and let two of our team members die 2v5 while /dancing to weaken the bots so they can go in and try to get their first penta. As soon as they go in I ult them. Did I mention I was playing Bard? Because I was. The bots turn on them the instant Stasis wears off and they get obliterated, much to the amusement of our team, only for me and the other survivor to go in and get an easy three kills.
I once mentioned to some friends who I know to be trolls a team comp of 
(Top, Jungle, Mid, ADC) with the sole intention of making their support player's life a waking nightmare. They did this... only for their support to wind up laughing about it and trying to troll them right back. Once mutual respect and trollage was established by the support Rocket Grabbing the enemy Amumu into a teamfight, they proceeded to establish an accord and make life a waking nightmare for the enemy team instead.
Sometimes I refuse to surrender because I dint care about the next ten minutes and I enjoy watching flamers flame
I like to troll my one friend, but it all started when I managed to mistakenly steal most of his jungle by firing blind Qs as support 
.
Afterwards I wall him in dragon and baron with , burst down kills before he can get assists with 
, and doing masterful plays as in URF.
Um... I don't have that many that come to mind.
Oh yeah, playing and shouting at somebody to grab the lantern, but the lantern pulls them into a worse situation...
Playing to only give the enemy team 4 free kills because you stuck your entire team in the stasis...
I've made too many troll walls on accident that I'm not proud of...
Headbutting people away and saving them as 
typing a emberessing thing for a friend but pressing shift getting all chat WHILE HES IN THE GAME /r
Accidentally stole a penta from my friend. He was mangry.
I stole a junglers first camp because i was late to the leash (supporting as 
) due to their jungler getting a bit close for comfort. I didn't realize they had already smited, and max ranged my Q. which took 4 seconds to land. And promptly killed gromp. I felt so bad, because they weren't a top tier jungler, and that first clear hurts.
Use 
ult and send the enemy over the wall that was protecting my low health ...
