Sony Ericsson DCU-60
The DCU-60 is a USB cable made for Sony Ericsson phones that use the FastPort connector.
Many people who have purchased a new-old-stock DCU-60 cable report that the silicone cable coating has dry rotted, and will crack and fall off after using the cable for some time. This leaves the cable vulnerable and it may stop functioning entirely.
(Author's note: I bought a DCU-60 twice and this happened to me both times.)