Baby Metroid

The Baby Metroid appears in the video game Super Metroid. It is a Metroid hatchling that grows attached to Samus and is kidnapped by Ridley towards the start of the game. After Samus defeats Ridley, she discovers that the glass case that contained the Metroid is broken, and the hatchling is nowhere to be found. When Samus discovers Mother Brain's lair, the now-enormous hatchling attacks Samus and begins draining her energy, but in the nick of time, it recognizes her as it's "mother" and flies off in shame. Later, during the final showdown with Mother Brain, the hatchling attacks Mother Brain just as she is about to deliver the killing blow on Samus. She kills the Metroid, but not before it bestows Samus with the Hyper Beam, enabling her to defeat Mother Brain.