These are some of the types of behaviors players use in Agar.io. Please note that these are not the official names of players.
All Modes[]
Splitters[]
Splitters are common but sometimes annoying players who try to eat smaller cells by splitting themselves with the space bar. Advantages: They gain mass quickly. Disadvantages: While split, they are more vulnerable. How to tell: If someone is split into 2 separate versions of themselves, 1 slightly bigger than the other. They are usually better than the average player.
Corner Lurkers[]
Corner Lurkers are less common players who try to eat smaller cells by hiding near a corner, and then trapping them. Advantages: They can easily trap a smaller cell in a corner. Disadvantages: They can easily be trapped in a corner by a larger cell. How to tell: if someone tries to bait you into the blank void using W mass. So be alert near corners.
Followers[]
Followers are common and very annoying players who chase after cells usually slightly smaller than them until they are trapped. Advantages: They are less of a target for other cells. Disadvantages: They do not gain mass comparatively quickly, and chasing a cell in 2 pieces can cause the opponent cell to merge and chase them back. How to tell: If you see a cell following another slightly smaller cell.
Virus Shooters[]
Virus Shooters are less common but dangerous players who try to split larger cells by shooting a virus with "W". Advantages: If they succeed, they can gain lots of mass. Disadvantages: If they fail, they have wasted some of their mass, and may hit the virus themselves. How to tell: If someone is staying behind a virus. Successful virus shooters can shoot with any number of cells and split to shoot a virus. they can also be better than an average player.
Bots[]
Agar.io - a fascinating bot
Example of a Bot
Not to be confused with Suicide Bots
Bots are AI and are basically almost NPCs. Many bots have plugins so that the owner can take control of the bots, basically overriding what the bot does. You can usually identify bots by their jagged movements.
FFA Mode[]
Leaderboard Cells[]
Leaderboard Cells are the large cells that are on the leaderboard and usually go after other leaderboard cells. Advantages: Their size. Disadvantages: they are more of a target for other leaderboard cells and virus shooters. How to tell: If their name is on the leaderboard.
Teamers[]
Teamers are cells that team up with other cells, feeding each other back and forth as necessary to eat cells. Advantages: Many. Disadvantages: hated by most cells, and get hunted. They can also be hit by the Anti Team Penalty, so watch out for them. How to tell: If there is one cell staying close to another cell and feeding each other.
Grazers[]
Grazers are rarer players who try to avoid other cells as much as possible, and only intentionally eat pellets and viruses. Advantages: Since they try to stay away from other cells, they are generally quite safe. Disadvantages: They gain mass very slowly. How to tell: If someone seems to be ignoring or moving away from smaller cells, even if they could have eaten them.
Bait Trappers[]
Bait Trappers are less common players that try to lure other cells closer to them by using one blob of mass as bait. Advantages: They can easily take unsuspecting cells by surprise. Disadvantages: they often fall victim to bigger cells that also get baited, and most skilled players know it's a bait by now. How to tell: If there is a single blob of mass in the middle of nowhere, there is likely a bait trapper nearby.
Suicide Cells[]
Suicide cells are rarer players that, for some unknown reason, commit suicide by running into a larger cell. They might be bots too. Advantages: None. Disadvantages: Dies multiple times and they get a lot of hate.How to tell: If you see a small cell moving into a larger cell seemingly on purpose.
Slow Teamers[]
Slow Teamers are Teamers that have adapted to the Anti-Teaming Mechanism, which was a system designed to punish teamers by making them lose mass faster. Slow Teamers, unlike Teamers on Party Mode, are less aggressive and only feed each other when needed. Slow Teamers often use tactics like splitting up slowly or barely ejecting mass unless needed.
Teams Mode[]
Bait Cells[]
Bait Cells are smaller cells who circle around large cells on the same team to lure cells on a different team closer. Advantages: Since they stay close to a large cell, they are usually fairly safe. Disadvantages: they can get eaten, although the big player can get mass, you'll die. they also get little to no mass. How to tell: If a smaller cell seems to be trying to stay a safe distance from you, but not going out of your sight.
Feeders[]
Feeders are team players that collect usually around 50 - 300 mass, and then feed it to a larger teammate. Advantages: If they get eaten, they do not have much to lose. Disadvantages: If the teammate that they have been feeding is not a very good player, then they are out of luck. How to tell: If you see someone feeding a larger player on the same team.
Cross-Teamers[]
Cross-Teamers are either suicide cells or feeders that feed a different team than the one that they are on. Advantages: they can avoid confrontation with their own team but can eat players in their own team. Disadvantages: they are hated by many players and kill their own teammates, this means they can't make a turnaround or stay on domination. Due to them getting hit by the Anti Team Penalty, all unlucky players "waste" their mass because of the penalty. How to tell: If you see someone feeding a cell on a different team large amounts of mass.
Stickers[]
Stickers are small cells that try to stick to another player. It is quite annoying to most players. Advantages: none. Disadvantages: It is hard to gain mass as the bigger cell gets most of it. and it can cause the big cell to die, and once the big cell dies, they are out of luck. How to tell: If you see one or more tiny cells sticking to a larger one.
Boosters[]
Boosters are cells that split into many pieces and push larger cells into smaller cells on the other team. Advantages: They help the big cell get lots of mass, and the larger cell, in 99% of all cases, will reward the booster cell. Disadvantages: They can be eaten by sneaky cells from the other team. How to tell: If you see a large group of cells pushing against a big cell.
Experimental Mode[]
Spawner Lurkers[]
Spawner Lurkers are experimental mode players who spend most of their time circling around one or a few spawners. Advantages: They are generally quite safe, as they can hide on the opposite side of a spawner if a larger cell comes. Disadvantages: they can't lurk around once they get to the mid game (1k+ mass) or else gaining mass will slow down to a crawl. How to tell: If somebody seems to be circling the spawner over and over again.
Party Mode[]
Suicide Cells[]
Suicide cells are tiny cells that move in a random direction until they are eaten. They are usually mistaken for bots. Advantages : none. Disadvantages : Very hard to get mass, big target for small cells. How to tell : tiny cells moving in one direction and not changing direction.
Suicide Bots[]
Bots are suicide cells always coming towards one player or that player's cursor. Because bots can be used with ease, and because you can gain mass without any skill, bots are sometimes used by players to cheat and get ahead. Despite the benefits, however, you may risk getting banned. Besides that, Bot services are also extremely shady, and some services have even fetched Facebook data to log into accounts so that their bots have larger starting mass. There is also a risk that you might loose previous skill that you've developed in the game.
Split runners[]
Split runners are people who team with another cell often splitting many times to get a tiny player or virus. Advantages: Both cells get mass quickly. Disadvantages: a skilled player can screw up the team's splitrun with 1 good split. For random teamers, one of the teamers may be "evil" and kill the other. How To Tell: 2 cells being hyperactive and splitting 3-4 times to kill anything that comes into proximity.
Multi-boxers[]
A single player who plays using 2 tabs. Advantages: No miscommunications, no need to find a teammate to split run with. Disadvantages: Very hard to control, and hard to react to danger. How to tell: When two split running teamers never both split at the same time.