Scorpion
Psychological (Freud)
In depth psychology the scorpion embodies the hidden sting: repressed hostility, resentment or self-wounding impulses lurking beneath a calm surface. It may also mirror the fear of an insidious betrayal, and so give image to the dreamer's own distrust.
Oriental reading
In interpretation after Ibn Sirin the scorpion usually stands for a slandering enemy or a two-faced person who stings behind one's back and spreads gossip. A sting foretells harm through evil words, while killing the scorpion heralds victory over such an adversary.
Animals
Dream interpretation is for self-reflection and entertainment — it is not a medical or psychological diagnosis.