The effects of cyber bullying aren't always obvious, but what if a victim was bruised like someone who was physically abused?
That was the idea behind one Irish boy's video to help promote online safety.
Thirteen-year-old- Luke Calhane created this video for Safer Internet Day 2016, marked today in the UK, to help young people adopt safe and positive online practices.
"I have been cyber bullied myself and understand first-hand the impact it can have on a young person's self-esteem," he told a local paper.
"I felt Safer Internet Day was an appropriate time to release this video to create discussion around the issue."
Watch the video.