Some ideas:
For an essay about pandas: While it might not seem like it, pandas are masters of camouflage in their forest environment.
For an essay about Rosa Parks: On December 1, 1955, Rosa Parks said no.
For an essay about space travel: Imagine holding on to the edges of your seat while hurtling out into distant space, dreaming of worlds beyond.
You don't have to use any of those, they're just suggestions. :) Happy essay writing!