To see a hydra or seven-headed serpent signifies temptation (Art). See symbolism of the serpent.
The Complete Dream Book
by Gillian Holloway
To dream you see a serpent, or seven-headed hydra, signifies sin and temptation.
About These Interpretations
This page presents 2 different perspectives on this dream symbol from various expert sources. Each interpretation considers context, emotion, and personal meaning rather than providing fixed definitions.