Zombie head
Plank (Unstable Foundations) was removed from RuneScape after an update, but still exists in-game for those who had obtained it.
[FAQ] • [doc]
Plank (Unstable Foundations) detail

A plank was used in the old tutorial, Unstable Foundations, specifically the part where the dragon had to be drugged - the plank would be picked up from the floor, to create a ramp allowing the player to reach the dragon's food bowl and put the drugged meat in it.