This week had quite an intresting twist where you had to create it from a given soundfile: Listen to the sound here
This large amphibian produces loud mysterious sounds that can be heard from the swamps with the help of it's heavily build chest and air sacks. It's used for attracting members of the opposite sex, as well as alluring smaller creatures to eat.
Visually, it also attracts smaller creatures with the thin "tentacles" attached on the shoulders with firefly looking lights towards the tip.
They are easy to detect, even when the swamps are densely packed with fog. It also fools smaller creatures by laying down into the water while only keeping the "fireflies" above it. This makes the huge creature appear smaller then it really is.