Beleif
Terrarian
The heads of spear traps, I have noticed, don't seem to know when to stop retracting. Because of this, they fly upwards until hitting a solid block and still have the ability to damage entities. This can be used as an exploit because spear traps are supposed to have a range limit while these don't. This makes them work as vertical, unpoisonous super dart traps.
EDIT: Oops, just looked on the wiki and learned that this was fixed in 1.2.3, which is not available for the mobile platform.
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