Imagine you and your friends are playing a fun game together, and then somebody comes in and starts doing things to make the game less fun. They might say mean or annoying things, or mess up the game on purpose. This is called trolling.
Trolling is when someone does things to upset or anger other people online. Sometimes, trolls do it just for fun or attention. Other times, they might have a specific goal in mind, like trying to get people to argue with each other or to disrupt a conversation or website.
Trolls often use silly or outrageous comments or posts to get a reaction from others. They might also use fake accounts, post controversial topics or opinions, or use insults or offensive language to provoke others. Trolls might also take advantage of people's kindness or trust, pretending to be someone else or lying about themselves to get a reaction.
Remember that it's important to be kind and respectful to others online, even if you don't agree with them. If someone is trolling you or making the online experience less fun, a good idea is to ignore them or report them to a trusted adult.