First I read them a poem by Shel Silverstein titled 'The Yippyuck' (about a thing called the Yippyuck which is not described in the poem). I then asked them to imagine, based on what they heard, what a Yippyuck would look like and drew it for them on the Smart Board as they described it, which turned out to be "big!", "fat!", "slimy!", "pointy nose!", "sharp ears!", "wings!", "fangs!", "evil smile!", "multiple eyes!", "five legs!", "duck tail!", "pig tail!", "antennas!". "tentacles!", "hair like medusa!", "halo!" .. needless to say we were all in splits by the end of this drawing session....! :)
If you ever wondered what a creature designed by a roomful of 4th graders would look like, well this is it: