This transparent jellyfish-like being occasionally flickers with a weird green inner light that steadily flashes on and off.
Speed 5 ft., fly 30 ft. (average)
Str 16, Dex 13, Con 15, Int 3, Wis 12, Cha 10
When slain, a marsh jelly explodes in a blast of acid that deals 2d6 points of acid damage to anything within 10 feet. A successful DC 14 Reflex save reduces the damage by half. The save DC is Constitution-based.
When a marsh jelly first takes damage, its body begins pulsating and flashing rapidly, emitting an eerie greenish glow. Creatures viewing a pulsating marsh jelly must succeed on a DC 14 Will save or be dazzled for 1d4 rounds. The save DC is Constitution-based.