Guurahk is the first Boss of Bionicle Heroes.
Kill the swarming Visorahk and collect the pieces, until you gain Hero Mode. Then use the Golden Constraction, which will hurt Gurrahk. Then use the rocks to block Gurrahks lasers until his Hearts turn red, and shoot him to deal damage. Repeat this until Gurrahk has half a heart, upon which he will stop attacking and no more enemies will spawn. Shoot him one more time to finish him off.