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Pet Rock

Pet Rock
Type Ghost
Developer(s) Thelibrarbian
Origin Undertale
Language(s) English, Deutsch
Sakura Pet Rock
Release date November 11th, 2018

Pet Rock is a ghost by Thelibrarbian, made for Ghost Jam 2018. It is based on the pet rock that may be found in Sans and Papyrus's house, in Undertale.

Upon opening the ghost, the user will be greeted by a note from Papyrus, gifting them the rock. The user may then choose a name and pronouns for their new rock pet. The rock does not require maintenance, but the user may pet it and feed it sprinkles to make it happy.

The rock does not speak, all dialogue is narration.


  • Available in both English and German; the language may be toggled from the config menu
  • Dressup items that can be applied in the items menu
  • Friendship system, where the rock will grow to like the user more if treated well, and despise them if treated poorly
  • Multiple interactions available through the ACT menu
  • The pet rock may be fed sprinkles, and the user may be prompted to feed it if it hasn't been fed in a while
  • The rock will remember the last action the user took, such as petting or interactions in the ACT menu, and the narration may comment on this from time to time
    • If the last action was petting, and the user pets again, they will get special dialogue about continuing to pet the rock


The rock has 3 dressup items, which may be applied through the ITEM menu, or through the right click menu.

  • Googly Eyes
  • Mustache
  • Party Hat


Pet Rock makes use of the Z - Undertale balloon by Zarla.