Ranboo was scared of water as a child. He didn't get over the fear until he met Tommy and Tubbo (this is talking as if they met when they were about 10)

One day after Tommy learned about Ranboo's fear brought him and Tubbo to a small lake and shoved Ranboo in a lot (about 20 times in the half an hour before Phil made him stop) this some how helped Ranboo get over his fear