Mime Jr. to Mr. Rime: Level up, knowing Mimic, then level 42, as the Galar form

Stages

Mime Jr. starts a line of three stages, from Generation IV

1. Mime Jr.#0439, babypsychicfairy
2. Mime Jr. to Mr. MimeLevel up, knowing Mimic
   Mr. Mime#0122psychicfairy
3. Mr. Mime to Mr. RimeLevel 42, as the Galar form
   Mr. Rime#0866icepsychic

How each step works

2 steps in the Mime Jr. line, 1 with a different rule in some games

Breeding

Mime Jr. hatches only when a parent holds Odd Incense

Without the held item the egg gives Mr. Mime. Item: Odd Incense.