A black cat appearing in your dream represents superstition and speculation. Depending upon your waking opinion of what black cats symbolize, either good luck or a bad omen, your dream cat may be tipping you off about what your subconscious self believes the near future has in store for you: either good or bad luck.
If the black cat is clawing or attacking you in a dream, then it means that you must accept the situation and should carefully go with your own instinct. You can no longer deny it but never forget to always proceed with caution.