Bunker Basher Fortnite is the pickaxe you'll need to use to collect Fortbyte #80 on top of the Volcano.
Smash the rock at the highest point of the volcano rim was the hint given to fans and the Bunker Basher was the requirement.
Bunker Basher Fortnite: How to Complete Fortnite Fortbyte #80
Snap into place.— Fortnite (@FortniteGame) June 3, 2019
Get the new Lock It Up Emote in the Item Shop now! pic.twitter.com/s2AEsM0RZt
The official clue for Fortbyte #80 states that it can be found by smashing a rock at the highest point of the volcano rim with the Bunker Basher pickaxe. Don't bother to search for this Fortbyte if you haven't unlocked the Bunker Basher pickaxe, which is a Tier 38 reward on the Season 9 Battle Pass.
The volcano rim itself is simple enough to find — after all, there's only one volcano in Fortnite. Once you've climbed to the top of the volcano or landed there, head to the northwest edge of the rim. There you should find a lone rock. Smack it once with your pickaxe, and it will disappear. In its place will be Fortbyte # 80, ready and waiting to be added to your collection.
Photo courtesy of Epic Games