If you looking of the episode of the same name? See The Precious, Wonderful, Adorable, Lovable Duckling (episode)
The Precious, Wonderful, Adorable, Loveable Duckling is a small black duckling and the main antagonist of the Season One episode The Precious, Wonderful, Adorable, Lovable Duckling.
He is a small black feathered duckling with a purple stripe on his neck. He has solid blue eyes and blue legs.
The duckling when first introduced is seen as an innocent and happy duckling who has a strong love for Eustace Bagge. This later becomes a complete obsession with him to the point he reveals himself to be a murderous psychopath. He attempts to kill both Muriel Bagge and Courage (even breaking Courage's leg) in various ways to have Eustace all to himself.
The duckling hatches out of an egg found by the Bagge family. It grows an immediate attachment to Eustace after he tried to eat the egg. Courage grows jealous of the duckling and eventually develops a hatred of it when it breaks his leg. Throughout the episode the duck makes various attempts to kill Muriel (which goes unnoticed to everyone but Courage) and Courage attempts to thwart him. Each time he screams for his "momma" and Eustace would punish Courage. Courage sneaks in after being kicked out again and finds Muriel tied to a large rocket by the duckling. He intends to launch the rocket to the moon but he gets his flipper stuck in the rocket while tending to it. Courage frees Muriel and despite his hatred for the sociopathic duckling, frees him too. Eustace interferes after hearing the duckling's cries and gets launched to the moon along with the duckling. On the moon the duckling gives Eustace a foot massage. It's unknown what becomes of the duckling afterwards.