Pets

The Pets part of Petscop.

There are at least 9 pets in Petscop; the Gift Plane sign suggests there are 48, while the menu shows space for 10 (albeit with one conspicuously empty). Of the nine that are known, 8 have been caught, with Care B being the exception.

Pets menu
The Pets menu is accessed from the pause menu under the (surprise) "" option. It initially shows every the first six pets in silhouette form; eventually Paul discovers the presence of an additional four slots on a page below the first. When a Pet has been caught, its icon changes to a full-color sprite with a white outline.

The menu options are X: Select Pet and Triangle: Go Back.

Child Library
When in front of the Child Library, the "Select Pet" option is replaced with "Drop". Attempting to drop any of the first six Pets results in a message popping up:

Otherwise, the pet appears to be set in the Child Library's return box. See that article for details.