Movie actor Robin Williams has been one of the most popular comedians for decades, and one reason is because he's a master of improvisation. He rarely abides by any prescribed script in his movies, and keeps everyone on the set astonished by what comes out of his mouth next.
What shows this wild and zany humor in his chart? First of all, notice that his Moon (mind) is conjunct Rahu, which is a wild, innovative, spontaneous, anything goes planet by nature. They're also conjunct in Aquarius, the most innovative, original, and inventive sign. In addition, they're both opposite Venus, his ascendant lord, which is the planet of creativity. This combination indicates someone with wild, zany, creative outpourings. The Moon is also the 10th lord so this connects these qualities to his career.
Notice also that Mercury, the planet of humor, is in the 10th house, conjunct the Sun, and quite closely aspected by Jupiter who's strong in its own sign in Pisces, an imaginative sign. This combination of Jupiter aspecting Mercury is often seen in comedians as I've shown in a previous article entitled, Swami Beyondananda, Wit and Humor.
Robin Williams Natal Chart