Answer:
Who cleans the ocean?
Devils, unicorns and goats all share this feature.
What's large on Saturday and Sunday. Small on Tuesday, Wednesday, and Thursday, and disappears on Monday and Friday?
I walk on 4 legs in the morning, 2 legs at noon, and 3 legs at night. What am I?
What is red, orange, yellow, green, blue, indigo, violet, red, orange, yellow, green, blue, indigo, violet, red, orange, yellow, green, blue, indigo, violet?
What starts with a 'P', ends with an 'E' and has thousands of letters?