A tier 4 wildstalker helmet is a helmet that keeps track of the amount of kills in the Wilderness of the wearer. Players may claim one from Mr Ex after 500 kills in the wilderness.
After 2000 kills, the wildstalker helmet will automatically upgrade to the next version, tier 5. Of course you can revert back to any of the previous tiers whenever you want.
A player performing the brag emote
Transformed into a statue