Inky and Winky are two of Felix's inquintitive and ingenious nephews. They first appeared in Felix the Cat Weather's the weather (1926) but are most famous for their appearance in April Maze. Since that, they have not appeared in any shorts, TV shows or movies but have been regular characters in a lot of the comic series.
In the Otto Messmer shorts, they are playful kittens that like to have fun with their uncle, although their crying when something goes wrong seems to agitate Felix in April Maze. In later incarnations, they are much more mischievous and often play pranks on Felix. Despite this, they still respect him and are supportive in his many adventures.