Metalium

Metalium is the stand of Henning, which is fought alongside him in his optional boss fight, as well as in the overworld, in Varanasi.

In-battle, the stand takes the form of numerous miniature tanks and helicopters, but it is able to assemble a version of any machinery drawn on a blueprint. It is an automatic stand, so the miniature helicopters and tanks caused rampages without Henning's knowing, but then he learned to control them like RC vehicles. Destroying the blueprint destroys the respective stand.

Event
In the southwest corner of the map, Henning can be found painting in his garage. Talk to him and attempt to rip up his blueprints to start a battle. Afterwards, all the miniature tanks and helicopters around town will vanish, and if you're with Jotaro, you'll get to watch a short conversation between him and Henning. You'll get +1 FP with whoever you beat him with as well. Cannot be fought on Josuke's route.