Choose an animal and get the children to all draw the same animal, "doing" something. You can get some animals doing some quite "wacky" things.
You may want to give each child a verb to illustrate in advance. These can make a nice literacy display, all put together.
Some ideas are, a bear - pointing, jumping, crying, smiling, driving, dancing, flying, sailing, skateboarding, swimming, skipping, ect
