If you go on google or learn Japanese yourself, you learn moshi moshi as a phone greeting in the language. It’s not appropriate for business or used off the phone very often, and can sometimes be considered impolite depending on the context. This phrase comes from telephone operators in the country that would use it as a phrase to test the connection of their phone and if the other person could hear them. However, moshi moshi is also used as a superstitious greeting by some because it is said that ghosts cannot say moshi twice, and foxes cannot pronounce moshi either. By greeting someone this way, you are basically proving you are not a ghost and not a nine-tailed fox pretending to be a human.
Especially these days you cannot be sure who is really a human or who is a nine-tailed fox, ghost, or some kind of evil spirit. You can even try saying it to yourself in private to make sure you are not a ghost or did not die at some point while staying here without a physical body. Unfortunately the effectiveness of this method is also limited in the western world because people do not speak Japanese. However, if your third eye is open you will be able to tell a ghost from a human and then if they try anything against you, you can sever their ties to the world with any blade, incense, or sage. Offerings of money work in theory but that’s a waste and I’m not paying ghosts for nothing in this economy. Giving them food also tends to work since these ghosts are not getting offerings of food or water which makes them become hungry ghosts and lash out.
Try using this greeting online or with friends who will not ask so many questions. Once you’re used to it, try it in other places. People may perceive you as being overly attached to Japanese culture when saying it, but when you have a superstitious reason for saying it people are more likely to understand.