n medium animal 

Perception +10; tremorsense 60 feet

Skills Acrobatics +10, Athletics +13, Stealth +12

Str +5 Dex +4 Con +2 Int -4 Wis +0 Cha -4

AC  21; all-around vision; Fort +10, Ref +14, Will +8

HP 70

Speed 25 feet, climb 25 feet, swim 25 feet

Melee [>] fangs +13, Damage 2d6+5 piercing plus amphisbaena venom

Ranged [>] spit +12 (range increment 15 feet), Damage 1d6 poison plus amphisbaena venom and blinding spittle

Amphisbaena Venom (poison) Saving Throw DC 18 Fortitude; Maximum Duration 6 rounds; Stage 1 1d6 poison damage and enfeebled 1 (1 round); Stage 2 2d6 poison damage and enfeebled 2 and slowed 1 (1 round); Stage 3 3d6 poison damage and paralyzed (1 round)

Blinding Spittle A creature critically hit by an amphisbaena's spit Strike is blinded for 1 round.

Twin Bites [>] An amphisbaena makes a fangs Strike with each of its heads, each against a different target. Both Strikes count toward its multiple attack penalty, but the penalty doesn't increase until after it has made both attacks.

Bestiary 3, page 15.