So, this is quite an interesting formation in the Waaagghhh Ghazghkull Supplement. Basically, you take Zagstruk and three Mobs of Storm Boyz, with the option to merge them all into a single, “uber” formation (which gives up multiple VPs if destroyed). Additionally, the formation has special rules that makes it only scatter D6″ when deepstriking and giving all members the shred USR for their Hammer of Wrath attacks.
This tactic would work especially well with a Green Tide style list, since it disrupts the enemy DZ, reduces his shooting, and allows those green hordes to get accross the table-top while you “hold” the enemy in place with the gian Vulcha Boyz mob. Put another way, you are limiting your opponents ability maneuver and shoot (i.e. reducing his options) while increasing the options for your own army. In this way, aside from any damage they do themselves, Da Vulcha Boyz formation is an excellent “force-multiplier” unit for many different Ork army styles, enabling the rest of the army to doe their jobs better, even in a competitive, tournament oriented all-comers list.