Jellyfish diameter; the tentacles and mouth parts usually extend beyond this bell dimension. The smallest jellyfish are the peculiar creeping jellyfish in the genera "Staurocladia" and "Eleutheria", which have bell disks from to a few millimeters in diameter, with short tentacles that extend out beyond this, which these jellyfish use to move across the surface of seaweed or the bottoms of rocky pools. Many of these tiny creeping jellyfish cannot be seen in the field without a hand lens or microscope; they can reproduce asexually by fission (splitting in half). Other very small jellyfish, which have bells about one millimeter, are
Space jellyfish luminous apparition is reminiscent of a jellyfish. The sightings of this phenomenon has led to panic, assumptions of alien invasion, nuclear missile strike, or plain UFO terror and hysteria. Space jellyfish A space jellyfish (or "jellyfish UFO"; also "rocket jellyfish") is a rocket launch related phenomenon that frequently is misidentified as an alien UFO. The phenomenon is caused by sunlight reflecting off the high altitude rocket plume gases emitted by the launching rocket, at pre-dawn and post-dusk, the twilight plumes. The observer is shrouded in darkness, while at high altitudes, sunlight is able to reflect off the exhaust that is