The Tortoise is a LegendaryTurtle Shield manufactured by Pangolin. Fabled Tortoise is obtained randomly from any suitable loot source, but has an increased chance to drop from Blue located in Caustic Caverns.
Special Weapon Effects
Win by a hare – Very high shield capacity, but reduced movement speed while active. Movement speed is increased beyond normal upon shield depletion. Greatly reduced health.
Notes
Effects that increase shield capacity based on a percent do not seem to add capacity based on the displayed amount. Amounts added by effects seem to be based on 40,000 to 50,000 capacity, and roughly 120,000 of the capacity is ignored. It is possible that most of the capacity is not counted because it is added by the Legendary effect and only the "natural" capacity is used in most cases.
You always have one of these movement speed effects:
While shield is depleted (current capacity at 0), running speed gets increased to about 150% of normal.
While shield is active (current capacity at 1 or above), running speed is reduced to roughly half of the normal speed.
Trivia
The flavor text references the story of a race between a tortoise and a hare; the tortoise wins the race even though he is slower because he is able to stay on task while the hare is distracted.
