Stabbing through walls
This is a glitch I noticed on the fishyard duel map, where the walls of the building can sometimes be stabbed through with a spear. The most successful location for this (and the one where someone accidentally did it to me) is right at the top of the stairs. You don’t need to be right against the wall for it to work, but it’s difficult to pull it off otherwise. The easy test is simply having the vanguard and the target get on opposite sides of the wall, as close as they can, then having the vanguard use the left click stab with the spear.