Most things underwater will leave you alone if you leave them alone. Most of these creatures are like that, but they have poisonous spines (or teeth) that can be thrust into anything that tries to touch or eat them...the toxins in their spines are extremely painful to humans (although generally not fatal), but are deadly to any other fish that threaten them.
Lionfish (1 foot long)
Leaf scorpionfish (4-5 inches long) sway in the current like a leaf
