CENTAUR: wear brown tights and have fake horse's end that rolls behind you on wheels.
ENERGIZER BUNNY: wear pink clothes, bunny ears, black sunglasses, attach cotton tail, and wear a toy drum. A hat box attached with rope will work if you can't find or want something bigger than a toy drum.
CHICKEN: big yellow hoodie with red comb on the hood (red glove affixed to hood will work), feathers or feather duster for a tail and a car wash sponge cut to be a beak. You can also add red tights to complete the look.
COW AND BUTCHER: one person wears a cow costume, the other dresses as a butcher. Cow costume can be found online, at costume shop, and sometimes stores like Target, and butcher's costume can be done with a big white apron, large rubber gloves, and plastic cleaver/knife, with fake blood smeared on the apron, knife, and gloves.
SPIDER'S WEB: Make or buy a spider puppet. Dress in all black, the tighter the better. A black leotard and black fishnet or spider-web pantyhose are good. Buy black hair netting, available at most grocery and drug stores. How many you need depends on your size and how much effect you want to create, but five hair nets will usually cover good deal of average adult. Pin netting so it hangs from arms and body. Wear black glove on one hand, spider puppet on the other. You can top off the look by drawing a web on your face with black eyeliner (use waterproof if rainy).
CHILD AS ANY ANIMAL: Fast kid costume. Get king-size white or colored pillowcase and rubber bands. Take each corner of pillowcase at seamed end and pull it through a rubber band to make ears of any length (rubber bands can be covered with yarn). Place this over the child to determine where to cut an oval for the face and holes for the arms. Cut out face and arm holes and then use make-up to decorate the child's face as the animal you've chosen this to be. Add a tail using a pom pom, string, etc. You can make the inside of ears pink with blush, acrylic paint or construction paper. Make spots with felt or colored paper. Use your imagination.
DALMATION: wear white clothes and draw black spots all over clothing. Paint your face white and use eyeliner/make-up to draw black spots on face. Tie two socks, which you have 'spotted', to headband for ears.
ROADKILL: wear all black, cut strips of yellow and red fabric or construction paper and attach them down the front of your outfit. Then pick your least favorite stuffed animal or buy a stuffed animal and pin it to your outfit. Gross but easy!
GOLDEN RETRIEVER: Get a brown sweatsuit, 3 brown tube socks and a brown knit cap. Used one of the socks for a tail by rolling it up and sewing or pinning it to the back of the sweatpants. Sew or pin the other two sock to the sides of the knit cap for the ears. For the face, use face paints to paint a dog face. For added effect, wear a collar and carry a large dog bone or toy.
THREE BLIND MICE: dress up with three of your friends! Buy mouse ears and a black rubber nose, which can be found most anywhere costumes are sold, wear matching gray sweatsuits, tails, dark sunglasses, and carry canes.
TIGER: wear orange sweat pants and hoodie, use a black magic marker or sharpie to draw tiger stripes on the sweats and hoodie, use orange felt or construction paper to make ears and attach them to the hood, add a tail, and use make-up to make your face look like a tiger (stripes and whiskers). Note: this also works for a white tiger costume. Just use white sweats instead of orange.
PREGNANT PUMPKIN: if you're in the late stages of pregnancy, have someone use face paint or make-up to paint a pumpkin on your belly, wear a button-down shirt buttoned to just below your breasts and pin the rest of the shirt behind your back and wear your pants low enough to leave your belly exposed. For added effect, walk around with your hands under your belly, to make it look like you're carrying a pumpkin.