Short explanation: Type ¯\_(ツ)_/¯ to see ¯_(ツ)_/¯.
Long expanation: Lemmy supports formatting, like italic becomes italic. To stop this from happening, you can put a \ before it like _; the \ isn’t shown. This is why ¯_(ツ)/¯ becomes ¯(ツ)/¯. To show a \ you need an additional \ like so: \, and to make sure _ is shown and not turned into italic, it too needs . This is why ¯\_(ツ)_/¯ becomes ¯_(ツ)/¯