Don't look too hard for Vincent, as he doesn't appear in the film at all! Instead, listen during the last scene after Bud and Lou have vanquished Dracula, the Wolf Man, and Frankenstein's monster. A cigarette hangs in mid-air and is lit by a likewise suspended match. Then a voice introduces himself as the invisible man. It's Vincent, briefly reprising his role from the 1940 Invisible Man Returns.  One only wishes he'd been included in the fun even more!

Glenn Strange as the monster, Lenore Aubert, and Bela Lugosi as Dracula (in the first time on film since his 1931 original).

Lon Chaney Jr. (who would appear with Vincent in The Haunted Palace), and Lou Costello.