Complex sentence: She appeared in more than a dozen, usually low-budget, movies, including voice work as The Monster's Mate in the Rankin/Bass animated film "Mad Monster Party" (1967), co-starring Boris Karloff.
Split into simpler sentences: She appeared in more than a dozen, usually low-budget, movies. She provided the voice of The Monster's Mate in the Rankin/Bass animated film "Mad Monster Party" (1967) co-starring Boris Karloff.