A globster is a mass of dead tissue that has washed ashore from a large body of water, and is usually composed of hair and either fat or blubber. Despite occasional anatomical landmarks like tentacles or bones, it is almost always unidentifiable as to its origins because it has decayed too much by the time it is discovered. (The card's effect makes globsters "wash up"--that tributing the first one leaves extra behind.)
The flame on its head is further insinuation of the globster's origin. Whale fat used to be the main source of lamp oil in the Nineteenth Century. (Globsters are usually debunked as being shark remains--so Metabo Globster is probably remains of a "Metabo-Shark".)
The fact that Metabo Globster is a water strider, paired with its flame-lit head, makes it reminiscent of a will o' wisp, in that it is a light that hovers over water.
2 more "Metabo Globsters" can be seen in the background.