- This card's name hints at its relation with "Lock Cat," (key and lock), with this card's effect being able to add 1 Level 3 or lower Beast-Type monster from your deck to your hand (Lock Cat), and Lock Cat's effect being able to Special Summon a Level 1 Beast-Type monster from your Graveyard (Key Mouse).
- This card is also connected to "Chain Dog" creating a key, lock, and chain connection.
- This card's effect deals with Level 3 or lower monsters. The syllable mi can mean "three" in Japanese, so this card's effect, when combined with its name, refer to Micky Mouse.