Greymon

Next, of course, comes the "adult" stage, who is no longer Tendonman's soul shrieking from the body of a dinosaur where he was no doubt imprisoned for the protection of the rest of the world, but Greymon DOES have a cool natural skull-helmet and breathes fire.

If you know nothing at all about Digimon, now is a good time to tell you that Digimon evolutions are not permanent. Digimon can, and often do, cycle all the way back to their baby stages, and main Digimon in the anime are especially prone to treating their evolutions more like temporary power-ups, reverting back to their more portable baby and child forms after expending so much energy in combat.

Digivolves from

 * Agumon

Digivolves to

 * MetalGreymon