Amphisbaena
About
A serpent with a head at each end, so that it can travel in either direction without turning, and one head always watching while the other feeds. It never sleeps in the sense that anything else sleeps. When it wants to move quickly it takes one head in the other's mouth and rolls. It is fond of cold ground and is the only snake anyone has seen out and hunting in frost.
Stats
Save Rolls
Traits
Special Attack
Both Ends: piercing, melee 5 ft, +4 to hit, 2d6+3, twice per round, and the two heads may attack in opposite directions. It cannot be flanked and there is no behind.
Special Defense
Two Heads, Two Pools: its 66 HP is split evenly, 33 to each head. Undirected damage applies to whichever head attacked most recently. A creature may declare a called attack against a named head, taking Disadvantage to do so, and all of that damage goes to that head. A head reduced to 0 is destroyed: the amphisbaena drops to one attack per round and begins regrowing it, which completes in 1d4 rounds and restores that head at 33 HP. Destroy the second head while the first is still regrowing and it dies for good. Let the window close and you are starting again. One Always Awake: while both heads live it cannot be surprised, snuck up on or attacked with Advantage from any angle.