Dismiss your construct by dismissing it from the pet window once you have completed the quest.
Thundering Cave Investigated
Description
The cavern that we opened at Baelgun's was the one place that most steered clear of... Can't say I blame 'em. The sound of thunder shot out of that cave, <name>! Loud, booming thunder!
I think near the end, it was abandoned by all. Bad, bad things happened to any that went in to explore - most never coming back.
I want you to check that cave out while you're at Baelgun's. Explore around the titan statue inside and report back with your findings.
Incredible! What could those iron menaces be up to? What are they doing in the Storm Peaks? And what is this Loken!? I'll forward this information to our central base of operations in the Dragonblight, <name>. I'll also let 'em know that you were invaluable in the acquisition of said info.
Loken yells: The three fissures opened by the mortals of this region must be silenced. The earth hears and sees what we do and will continue to interfere with our efforts if the way is not closed.
Loken yells: Bury this place! Your master demands it!