Here's why:

* Alloy in ballpoint pens: Tungsten is used in the tips of some ballpoint pens due to its hardness and wear resistance.

* Nearly twice as dense as lead: Tungsten is indeed significantly denser than lead.

* Strong odor: Tungsten itself doesn't have a strong odor. However, tungsten oxides can have a pungent odor.

* Highly toxic oxide: Tungsten oxides, particularly tungsten trioxide (WO3), are considered toxic.

Important Note: While tungsten is a heavy metal, the amount used in ballpoint pen tips is very small and poses no significant health risk to users.