This brazilian urban legend is called: Juliosan
Juliosan is a spirit of an 8 year old child that drowned inside the toilet, Juliosan likes to scare and kill victims that dares to disturb him
To summon him, you have to go to the 3rd stand of the bathroom of the 3rd floor, and say "first julio, second julio, third julio", after that, juliosan will appear and open the door, and hang you to death
Another way to summon him is going to the 3rd stand of the bathroom of the 3rd floor and knock on the 1st stand, then the 2nd stand and in the 3rd stand 3 times, after that, turn off the lights and say: "Juliosan?" After that, juliosan will say: "Hello there", and enlongate his body and throw you into the toilet.
You can also find him by random
Powers
Enlongate his body
Teleport
Run very fast
Habitat
Juliosan can appear in every single bathroom, even house bathrooms, however, he appears in dirty bathrooms more often.
Discovery
A man describes how he discovered that Juliosan was in his bathroom all the time, one day, his childs started to disappear misteriously, and his wife was found dead, unable to figure out what was happening, he decided to investigate his bathroom, one night while pretending to sleep, he started to feel an sensation of something wandering around in his house, then, he witnessed Juliosan jumping out of the toilet and enlongating his body to climb out of the bathroom, the man fleed to the mountains to never, ever return back
Other things to keep in mind
Don't try to run away after doing the ritual, because if you run away, he will teleport and kill you.
If you realize that Juliosan is in the bathroom, run away as fast as possible out of the bathroom.
While doing the ritual, don't let any light turned on.
Remember, if you're doing the ritual and there's someone in the bathroom, you will put his life in danger too.
References
Juliosan reminds 3 urban legends, Bloody Mary, The Blonde girl in the bathroom (Brazilian urban legend) and Hanako-San (Japanese urban legend)
Juliosan also reminds the character "Murta Waren" from Harry Potter, this character was a girl that got killed by Voldemort, and she likes to scare people in the bathroom.