The Lobster Monster is a large lobster-like monster from the 2017 Continuum.
The Lobster Monster resides in the Cave of Ali Baba, where it guards its treasure. When Scrooge McDuck and family discovered the cave, the Lobster Monster naturally attacked them. The Monster is actually sentient, capable of speech, and even the owner of a wristwatch; he was insistent that the Ducks hurry up with the adventure, as he had somewhere to be soon after.
Behind the scenes
The Lobster Monster first appeared in the DuckTales 2017 theme song.
It is one of the characters specifically created for the series, who presumably does not have a counterpart in the regular universe. However, it does appear in he same location as the Roc in the Carl Barks painting The Cave of Ali Baba, so that it may loosely be considered the 2017 Continuum's counterpart of the Roc. Moreover, it is similar to the Giant Scorpios seen in Treasure of the Lost Lamp.
The Lobster Monster is featured in the fourth-wall-breaking Turn Off Your Phone PSA, which establishes its ability to talk.