You have to go through the air vent (and find a way to open it). The “key” is not far from the vent.
THANK YOU SO MUCH!!! I just finished the game and I loved it :D
The only thing I see close to the vent is the coin, which is also out of my reach.
There’s a way to loop stand and walk on the ceiling in the area by the coin. The eel can help with this.
Thanks!
Lovely game!