This mod adds the following materials from the Undergarden to Tetra:

• Cloggrum
• Froststeel (including Frostbite ability)
• Utherium (including Rotbane and Bloodlust abilities)
• Forgotten Metal (including Threnody of the Deep ability)
• Smogstem
• Wigglewood
• Grongle
• Depthrock
• Shiverstone

Pretty much all the code is from Tetra's mickelus and the Undergarden's quek.