The Big m'ungus got tired of needing to catch their poolloons to eat them and also wantead to make life on a gas planet easter so they practised eugenics ‘n crud and can fly now. They use their giant wings to stay airborne in the gas planet and have giant toothy mouths to eat poolloons. Their eggs can fly because they have an air sac in them and so are tiny blimps so they don't fall into the centre of the planet.