Heavy weaponry and a ton ammo are your strengths, but even that cant prevent the forces of nature...

Storyline:
2 years after a deadly infection ravaged earth, the UNSC sent out 50 MHSU's. These Movable Human Survivor Units were designed to hold and protect 30 survivors for a short period of time, just long enough to reach a safe zone.
Unit 41 was scheduled to rescue 16 humans from a desert outpost. It was meant to be a 2 hour mission, in and out. The pick up was successful but they never got out in time...

Gameplay:
-Best played with 8 to 16 players
-Use the variant "Seekers"

Download:
http://www.bungie.net/Online/Halo3UserContentDetails.aspx?h3fileid=100938596
http://www.bungie.net/Online/Halo3UserContentDetails.aspx?h3fileid=100938599

Pictures:

Human spawn in MHSU no. 41.

Zombies start atop the desert outpost.

The MHSU

When a zombie dies they will respawn here. Spawn killing is impossible as there are 5 exits and the zombies are tougher than you.

After 2 minutes the MHSU flips. Your safe haven now becomes destroyed and you must quickly flip your vehicle or else get slaughtered by the zombies.

Once your unit has flip and crashed you become an easy target for the zombies.

Its sinking

This map is quite fun play. The humans can easily overpower the zombies at the start, but once the MHSU has crashed the humans become easy prey.

Other Notes:

Its really funny when you 16 players all on unit when suddenly it flips. Everything goes flying in all directions, humans and objects alike.
Also if you happen to fall off the unit whilst its moving you cant get back in unless the driver stops.

Enjoy.