The Grand Paradox

Ecology
The Grand Paradox is a chaotic and unstable manifestation of temporal instability, often appearing in the Gear-Plains of the Chronos-Clock. It is an amalgamation of three different "pruned" timelines, appearing as a flickering, multi-armed humanoid that exists in multiple states of existence simultaneously. It is a byproduct of the "Stillness" attempting to overwrite the current reality.
Combat Mechanics
In combat, the Grand Paradox is exceptionally difficult to track. It can act multiple times in the initiative order, with each action representing a different version of itself from a different timeline. It possesses a "Temporal Blur" that grants it a high displacement-based AC. When reduced to 0 hit points, there is a 50% chance it will "Reset," returning to the state it was in at the start of the round, unless it is killed by chronomancy or force damage.
Loot
Upon its final dissolution, it leaves behind a "Paradox Shard." This small, glowing crystal allows a user to reroll a failed saving throw once per day by briefly tapping into an alternate timeline where they succeeded.