Serpentine's venom could debilitate a gem enough for them to retreat back into their gem. Of course if enough venom is applied. Or it can physically corrode their gem itself. I don't know, just shooting ideas.
Name: Serpentine Gem: Appearance: She has fangs that can grow longer depending on her mood. Gem Placement: Left eye Gem Item: Gem claws that extend from her hands Power: Binding Tendrils Other: --