Manners 
To dream of a well-mannered person implies that an issue you believed to be impossible to resolve will actually prove to be much easier.
To see an ill-mannered person indicates that disharmony between you and a partner will prevent you from completing a project.
Mansion
To dream of a mansion represents your ability to achieve elevated goals and spiritual discovery. Perhaps your present position in life is stagnant and not progressing in the way you desire.
Manatee
To dream of swimming with a manatee indicates a warm and gentle personality.
Multiple manatees suggest it may be time for some rest and relaxation, and possibly even a trip to a warmer climate. There is also a suggestion of a little sadness.
To dream of a manatee mother and baby advises you to be loving and soft to yourself at this time.
Manicure
To dream that you are getting a manicure symbolizes fascination and allure. You want to be noticed and praised for a task that you have completed. Perhaps you are trying to communicate your creativity via some project you are undertaking.
Mantilla
To dream of a mantilla indicates that you will embark on an unscrupulous or negative endeavor and suffer disgrace and humiliation as a result.
Blackout
Experiencing a blackout in a dream suggests that you're being cut off from something which could be anything from civilization to a specific person or resource. Whatever the case, you feel that you need this contact or resource in order to be successful and you feel 'in the dark' without it/them.
Mannequin
To dream of a mannequin implies that you are being too passive about some issue in your life. It is a symbol of your personality or some characteristic. Pay attention to what the mannequin is wearing to search for meaning. Perhaps you are avoiding something that you need to say or do.
Blackbird
To see a blackbird in your dream is a sign of bad luck to come. It can also indicate that you do not feel the drive or determination to complete a task or achieve a goal.
To see a flying blackbird in your dream means that you will experience prosperity or good luck.
Blackmail
To dream that you are blackmailing someone implies that you strive to win at any cost, even if it means hurting someone else.
To dream that you are being blackmailed indicates that you feel vulnerable and exposed. You are doubting your potential to succeed. It may also represent a 'black male' who you associate with.
Manta Ray
In a dream, the manta ray symbolizes a deep connection to the subconscious. The manta ray lives near the bottom of the ocean, hiding itself in the sand. If a manta ray reveals itself to you in a dream, you are being exposed to a hidden secret within your mind. The manta ray is graceful and effortlessly glides through your subconscious. The manta ray makes an excellent guide to knowing yourself better.