Bat-Mite

Depicted as a small, childlike man in an ill-fitting copy of Batman's costume, Bat-Mite possesses what appear to be near-infinite magical powers which could be considered nigh-omnipotence, but he actually uses highly advanced technology from the fifth dimension that cannot be understood by humans' limited three-dimensional views.

Unlike Mxyzptlk, Bat-Mite idolizes his superhero target and thus he has visited Batman on various occasions, often setting up strange and ridiculous events so that he could see his hero in action.

[2] Bat-Mite was retired from the comic in 1964, when editor Julius Schwartz instituted a "New Look" Batman that shed some of the sillier elements in the series.

Bat-Mite and Mr. Mxyzptlk teamed up four times in the pages of World's Finest Comics to plague Superman and Batman together, as well.

[5] In 1964, the Batman titles were revamped under editor Julius Schwartz, leading Bat-Mite to stop appearing.

Cover to Detective Comics #267 (May 1959), the first appearance of Bat-Mite, art by Curt Swan .
Bat-Mite (left) as depicted in The New Adventures of Batman .