It is in astro knight island. There is a secret in the libary in the castle that helps you.
Click on it!
Get the cheese from the dungeon and use it on the mouse
No mouse. Just a ghost cat.
with your mouse
You feed the owl the robotic mouse that is in the castle
if you have the mouse, release it
you give it to the owl.
You Get Cheese
to get the mouse eaten in poptropica you have to go to the messed up library and theres a book you have to click and it opens a secret room you have to enter then you can release the mouse and after you exit you have to find a new entrance.
you use the mouse and click
press 99
You get the chese for a mouse in the left room in the destroyed castle in astro knights in poptropica