From Stardew Valley Wiki

Junimo Plush Can be placed inside your house. Information Source(s): Pelican Town

(bush in NW corner) Sell Price: Cannot be sold

right-clicking

Theis a secret piece of furniture . It can be found bya bush in the northwest corner of Pelican Town on the 28th of any season at exactly 12:00pm.

The instructions for finding the Junimo Plush can be found in Secret Note #13, though finding the note is not necessary to collect a Junimo Plush from the bush.