Used in the expression, "I want to stab *insert something here* with a rusty wooden spoon." A rusty wooden spoon is meant to be a painful yet insulting form of attack. The fact that it's a spoon means is important because spoons are blunt. To stab someone with a sharp object would be giving too much dignity to the stabbee. The fact that it is wooden makes it even more insulting because wood is much softer than metal and wooden spoons are also much more uncommon. The rust is mostly there for insult, even though it could, possibly, lead to infection. Practically, this object can not exist unfortunately. There is the slight issue of wood being unable to rust. The closest we can come to this goal is to have a wooden spoon that has been coated with rust from something else. That will simply have to do.