Answer:

serpents

Answer	Crossword Clue
SERPENTS	Very large snakes
SERPENTS	Slithering hissers
SERPENTS	Treacherous ones

SERPENTS	Treacherous types
SERPENTS	Cobras, kraits, etc.
SERPENTS	Hissers
SERPENTS	Snakes
SERPENTS	Malicious types
SERPENTS	Boas and cobras
SERPENTS	Herpetologist's subjects
SERPENTS	Some reptiles

SERPENTS	Zigzag fireworks.
SERPENTS	Reptiles.
SERPENTS	Treacherous persons.
SERPENTS	Sea ....
SERPENTS	Caduceus symbols.
SERPENTS	Treacherous ones.
SERPENTS	Herpetologist's concern.
SERPENTS	Ophidia.

SERPENTS	Pythons.
SERPENTS	Sea phenomena.
SERPENTS	Sneaky ones.
SERPENTS	Boas
SERPENTS	Apophis, basilisk and cockatrice
SERPENTS	These got in Medusa's hair
SERPENTS	Medusa's tresses
SERPENTS	"How sharper than a ... tooth . . . ": Shak.

SERPENTS	Ophidians
SERPENTS	Herpetologist's pets
SERPENTS	Ancient marine "hazards"
SERPENTS	Deceitful ones
SERPENTS	Asps, e.g.
SERPENTS	Large snakes
SERPENTS	Caduceus features