The Horned Stranger is a Stranger. Being as large as the Boss Stranger, the Horned Stranger is actually much slower than the others, but if Aya gets some distance it can charge which turns into a head butt or a jump ambush. The Horned Stranger also possess a much different attack pattern then any of the other Strangers. It attempts to ambush Aya as she enters the Neo Ark Forest, and can retreat into the underbrush and appearing again in front of Aya.
An easy way to deal with them is any Grenade Launcher as it will knock them down. With a second grenade shell, it can easily be killed. It is important to keep these around as it will make short work of them. But if you don't have the luxury of Grenade's there are other ways to tackle these Strangers. If you are quick enough and smart enough you can trick them into biting thin air, then you can attack them from shooting their backs, this is their weak spot which is indicated with a purple flash around the damage bar.
Another decent way of tackling these guys is to knock them down using Plasma or the stun-gun, allowing for critical hits on its weak spot, killing them very quickly.
Although slightly underrated and unpopular the bayonet attachment makes an easy task of killing these strangers as sometimes a single slash to their back (spine) is enough to terminate them.