The mechanical mouse, which can be captured using cheese, is eventually food for the robot owl Merlin, who is found in Mordred's secret underground lab.
(see related question)
You release it near Mordred's owl invention when it flies out of the underground lab. The owl eats the mouse (though it may still be in your items) and will follow you. To have the owl retrieve something, click the mouse, then the object.
To get the mouse out of its hole on Astro Knights Island, you will need to acquire the cheese from the bakery and then place it near the mouse hole. The mouse will be attracted to the cheese and come out of its hole. Then you can capture it to progress further in the game.
There is some cheese in the dungeon beneath the library.
Get the coin from the fountain next to the museum. Pay your admission and get the Library Slip from the stack of books. Go to the castle library (first floor right) and on the lower (nonfiction) aisle is a scroll near the sign "M-Mc" -- press it to open the stairway into the dungeon. Get the cheese and pull the lever, then leave. Use the cheese to get the mouse in the maid's room (first floor left).
go to your inventory and go to the mouse and click release
the mouse is in the princesses room in the hole in her wall but you have to get the cheese to get him/her.
they are around it and you have to lead them 2 the black hole
There are no fish on Astro Knights Island. There are Space Sharks around the Ice Planet at X-73 Y-83. To defeat them, shoot them and lure them to the Black Hole at X-85 Y-47. (see related question)
You get him close, and go slowly so he follows you to the black hole. You just need him to go into the black hole.
Still in the dungeon. Either the hole is too small, or he doesn't like dirt caves.
When the space sharks are chasing you, get close to the black hole and circle around it while not going in. The sharks will be caught and dragged inside.
ya just take them to the black hole around the other planet
you get them in the black hole
go back up the stairs or back through the little hole
you have to go to the hole between the bales of hay and tell the owl thingy to get it by clicking the owl and clicking the green thingy
The black hole is at X-85 Y-47, up and slightly to the right from the Ice Planet. Its only use in the game is to dispose of the Space Sharks. (see related question)
You shoot the space sharks, and run away slowly. They follow you, so if you get them near the black hole, they get sucked in. (Black Hole is up and left, at X-85 Y-47.)