A large spider like robot capable of destruction on a large scale featured in the anime and manga Needless.
The testaments are used by Simeon and Adam Arclight's group in the Needless hunt to patrol as well as control the populace and track down enemies . Riru secretly builds giant testaments which she reveals at the Simeon HQ when the people try to leave as Arclight and Blade battle.
Disk has many refurbished testaments in Iron mountain to protect her.
In the manga Disk uses a testament to travel long distances when she is only a head.