Hub 5: Vivarium

Vivarium is a bonus level in Hub 5: Necropolis in Hexen.

Walkthrough
This level is optional, but it will provide lots of helpful items for the final hub. As the intro suggests, the entrance portal is only available before you enter any of the tombs, after which it is closed off.

There are face-like walls that shoot Porkalator charges at you, among other unpleasant things. Let one of those charges hit you, then, in your pig form, run through the small passage near the starting point. It leads to a secret room with a lot of goodies. Then wait until you're human again, pick up everything you can and open the huge door leading out.

To get back to the hub, you'll have to jump onto one of the ledges to the north. It can be tricky, so jumping on one of the statues first helps.

Variations
Depending on which character class you play as, different enemies appear in the level. As the Fighter, there will be Centaurs, Slaughtaurs, and Green Chaos Serpents. As the Cleric, you will face Dark Bishops, Brown Chaos Serpents, and Ettins. As the Mage, there will be Reivers, Afrits, and notably Wendigos, who otherwise only appear in the first hub. While there are always Ettins present, there are more for the Cleric.