This strange creature described as a fairy resets all growth on eggs, reducing clicks to 0.
This item resets clicks on eggs back to 0, reversing the egg sprite back to its original form at stage 0.
In the announcement, a longer version of the description is included:
This strange creature described as a fairy resets all growth on eggs, reducing clicks to 0. The instructions read: Release the cap, pull the tag to imbue fairy with timeless sand, and point in direction of egg. Someone appears to have hijacked the label, crossing out the original name and replacing it with "S U P E R G L". There was not enough room for them to finish.
On the inventory page, the Rejuvenating Fairy is listed as a Rejuvenation item. However, it can be considered a potion.