Stan Lee: Terrigen Assist
In the lower levels of coreward Attilan, find Stan Lee about to be forcibly Misted.
Start by a smashing a glimmering crate stage left. It doesn't look like silver, but you need an anti-silver attack to destroy it anyway.
Construct the pieces to open up a control console. Here, you can use the up and down arrows to raise and lower the temperature, respectively. Despite the dire warnings, you actually want to raise the temp here.
The pipes heat up, exposing some silver connectors. Blast 'em.
That takes the stage left side of the mister out of commission, now to stage right. Start with another crate-destroy and console-construct, just like the other half.
On this console, you'll want to lower the temp, until ice crystals form.
This completely shuts down the machine, releasing Stan, and winning you a brick.