When awake, Blackholetchi takes the form identical to a massive, black squid-like creature with five tentacles, a large head, and a mouth with a giant purple swirl inside. When Blackholetchi is asleep, he takes the form of a giant, swirling black hole and will suck anything within range into his stomach unless he's woken up.
Despite its massive size, Blackholetchi is a gentle and understanding Tamagotchi that doesn't mean any harm. However, he's also very drowsy, and often doesn't realize the damage he causes until he's woken up.
On Virtual Pets
Tamagotchi: The Movie
Blackholetchi is first encountered asleep, accidentally starting to suck the rocket piloted by Mametchi and Tanpopo into his mouth. The group mistakes him for a legitimate black hole, but Mamehakasetchi hears the snoring coming from the center of the hole, and realizes it's really Blackholetchi.
They attempt to wake up Blackholetchi by shouting at him using the speaker on the outside of the rocket, but a stray rock becomes lodged in it. Mametchi and Tanpopo are forced to go outside the ship and dislodge it, and are sucked into Blackholetchi in the process. With every Tamagotchi on the Tamagotchi Planet chanting for Blackholetchi to wake up, the Planet itself suddenly lets out a shout loud enough to wake him up. Upon awakening, Blackholetchi pulls Mametchi and Tanpopo out of him, apologizes for accidentally swalling them, and sends them and the rocket back to the Planet.
- Blackholetchi's voice actor is not credited.