Towards the end of the classic era of Looney Tunes, during the Warner Bros-Seven Arts period, WB tried to come up with new characters that would catch on with audiences and replace the older characters who had arguably become passé. To this end they created turds like Cool Cat and this gem, Merlin the Magic Mouse. Merlin is a mouse that also happens to be a magician and he sounds like W.C. Fields and has a sidekick named Second Banana. All of those things sound like WB was really in tune with the audiences of the late 1960s, right? This first cartoon in the mercifully short series has Merlin trying to put on his magic routine without tipping off his sole audience member, a cat, that he's a mouse. He does this by putting on...sigh...putting on a fake mustache. This bit is annoying enough but it's made worse by the sidekick character spelling out the "joke" for the audience of presumably bored viewers.
Like other WB cartoons from this period, the quality of the craftsmanship is poor. The animation, writing, music, sound effects are all subpar even for TV of the time. The only thing remotely good about it is the voice work of legend Daws Butler, but he can only do so much. I especially hate the music, which is stock crap and grates on your nerves within the first minute.