Tiberium

Warning: Spoilers follow

In the computer game series Command and Conquer, Tiberium is an alien crystal that suddenly appears on the Tiber River in Italy in 1995. It leaches metals out of the soil, leaving it depleted and forms vast beds of crystalline Tiberium. It is suspected that the Scrin, an alien force that was observed by both GDI and Nod, is the culprit who released Tiberium upon the Earth.

The Scrin posessed an artifact, which Nod dubbed the "Tacitus", that can control the growth of Tiberium and its mutagenic effects. Nod also employs Tiberium Gas missiles.

Over time, it is discovered that Tiberium mutates living things and can create some rather disturbing creatures.

In Firestorm, CABAL (under Kane's control) attempts to create new variants of Tiberian life. Nod and GDI form a temporary alliance to stop the mad CABAL and prevent its Cyborgs from taking control.

Varieties

• Riparius - Color: Green. This is the first form observed. It is spreads rapidly, but has a rather low concentration of leached materials.
• Vinifera - Color: Blue. This is the more potent and highly explosive variant of Tiberium. It is extremely valuable, but mutates living things much faster as well.
• Gas - This is a dangerous form of Tiberium which forms toxic clouds. Often observed being emitted by Tiberian Veinhole Monsters.
• Sea Tiberium - Tiberium that poisons and clogs waterways. The oceans are mostly filled with this form by the time Tiberian Sun takes place.

Tiberian Life Forms (mutants)

• Mutant humans - Some humans aren't completely mutated by the Tiberium. They have varying degrees of mutation and many have embedded crystals of Tiberium.
• Tiberian Fiend - Looks like a giant dog. Spits shards of Tiberium at high velocity.
• Tiberian Floater - Looks like a big jellyfish. Can build up an electric charge in its tentacles and can release Tiberium gas to propel itself.
• Veinhole Monster - A mouth in a hole marks the heart of this creature. It grows veins outward, which hold the precursor to Tiberium Gas. When attacked, the monster releases the gas, poisoning its assailants. The veins also attack heavy vehicles that drive on them.
• Visceroid - Formless blobs of Tiberium mutated flesh. Can attack with a pseudopod and moves very fast.