metastasize

(mĭ-tăsˈtə-sīzˌ)

1. To be transmitted or transferred by metastasis.
2. To be changed or transformed, especially dangerously: “a need for love that would metastasize into an insatiable craving for attention” (Michiko Kakutani).
3. To spread, especially destructively: “[disinformation] … that even now continues to metastasize … to such a degree that myth threatens to overthrow history” (Gore Vidal).