Bad / Dangerous
tremor - A slight shaking movement, such as one caused by an earthquake or instability; also a subtle or faint sign of emotion, such as fear or excitement in the voice or body.

Because he was nervous, his voice had a significant tremor during the presentation.
caustic - Sarcastic or severely critical, often in a hurtful or biting manner; or able to burn or corrode organic tissue, typically referring to chemicals or substances.

The caustic chemical spilled onto the floor and quickly started to eat away at the floor surface.
hysteria - A state of extreme excitement, fear or anger in which a person, or a group of people, loses control of their emotions and starts to cry, laugh, etc.

There was almost mass hysteria when the band played their final song and some in the crowd rushed towards the stage.