If the enemy team has any Swain skin, especially Northern Front, I know this is going to be more of a torture session than a game. Justicar Syndras are usually terrifying to play against.
On the flip side, Pulsefire Ezreals tend to suck, Assassin Yis tend to be most likely to rush an IE in the jungle and feed, and SKT Zeds tend to fall apart if their team doesn't perform to their MLG standards.
Lollipoppy.
Nutcracko Noxian or Scarlet Hammer Poppy Giant Enemy Crabgot
Super Galaxy Rumble on the enemy team. Not because the player will be good, but because you know you have about 10 minutes before your toplaner goes AFK.
Definitely Not Blitzcrank.
Just because I'm not sure what his abilities are... I can't even figure out who it is. Maybe it's Bob, from accounting? What's Bob doing on the Rift?
Championship 
Because thats when you know shit is about to go down.
Surprise Party Fiddlesticks: When he Ults ME: What is happening?!!!
King Rammus
ultimate skin. They are either the godyr, or they are just a little bambi. No in between.
I'm afraid for my team when I see Battle Bunny Riven on my side. On the other side a Mistletoe LeBlanc is likely going to wipe the floor with our mid laner.
You know you're fucked when you see Gladiator Draven
Cottontail Teemo. I can't even.
dunkmaster darius just because you know he's going to be an asshat in chat when he inevitable dunks you
GET DUNKED BITCH
well I have 80 cs to your pitiful 30 cs
I dont care
LATE GAME
over 1000 stacks why hello there over
built full damage uhh hi
Battlecast Vel'Koz. Arclight is generally considered better (though I respectfully disagree), so most people using this have been playing Vel for a looooong time. If you don't understand why that should scare you, you haven't seen a good Vel'Koz.
Any 
skin. I already want to afk when i see any yorick in my lane...
and if he has a skin :''''''''''(
Classic skin 
.
Either this guy is going to start the game by taking two buffs at the same time while simultaneously ganking a lane, or he'll level his Q/E first and wonder why the jungle is so difficult.
Gladiator Draven, Nutcracko, Curling Veigar.
Workshop shaco.
Nightblade Irelia.
It's the to-go skin of all Irelia mains i have ever seen.
Battlebunny Riven and Pulsefire Ezreal are the biggest feeders and flamers. Championship Riven and either Frosted or Nottingham Ezreal are usually pretty scary to play against. If you see Masked Shaco on the enemy team you better not ever move past the first quarter of your lane.
Dark Valkyrie; no-one buys this skin for her except die-hard Diana players.
Enemy team:
Any skin. If they have Yorick and a skin for him, they are most likely an avid player and will wreck your face.
Armor of the Fifth Age skin. He will steal everything you hold dear and look absolutely dashing while doing it.
Black Belt skin. I cry whenever I see one of these, because the only time I ever see it they are absolute monstrosities and take over a game in mere minutes.
My team:
Mecha skin. They usually play really aggressive and often end up either snowballing out of control or feeding to heaven and back.
any skin. They are likely a "Riven main" and the match will either end with them KS-ing every single kill and raging at us for being scrubs, or them feeding in lane and AFK-ing at 10 minutes.
Dragon Slayer skin. They are usually very cocky (even for a Vayne) and have a higher than average tendency to rage at our support.
Steel Legion 
- You know this guy is going to pub stomp.
I don't like going against Zombie Brands because they seem to do so much damage and never miss skillshots.
Headhunter 
+ Championship 
I'm in some hard times.
Separately, they're nothing though.
Uh. Championship riven.
Pulsefire Ezreal scares me... if he's on my team.
I'm afraid of battle bunny riven.... on my team. They feed 75% of the time. boom boom and piltover customs blitzcrank will wreck your shit Don't think I've ever played agaisnt a bad headhunter cait
Any skin. An un-killable bird monster that somehow heals more damage than your team can dish out.
Noxus Poppy. She will make your skills look like poopy.
Triumphant Ryze. Don't leave your fountain. Scratch that, you CAN'T leave your fountain.
Any of the old skins. Playing this dude since his release, they will make your life hell.
Zombie Brand. I swear they all use hacks.Finally, as a Pulsfire player I feel kinda offended at all the hate that skin gets, I only bought it because it reminded me of playing Tron 2.0. (If you have not played this game, go do so. NOW.)
