My own imagination randomly spawned this machine which never appeared in the book itself. I remembered back to one scene where one of the machines picks up a couple of fleeing humans in its tentacles and tosses them into a metal basket on its back.
The martians themselves feed on blood, and inject human blood into them to feed, since they lack any digestive system. So I thought up a sort of " harvesting" machine that could go out and "pick" a nice patch of humans, sling them into its basket and frolick on back to its base. War Machine and Gardener...two in one...though Fighting Machines did this as well, the idea of a slicing, impaling moving appendage had to be put to use.