Hi Inspector Dim!
When you notice the icon in the menu bar, and I presume you mean the far right section ... it has its own name but I digress ... when you see the icon appear, launch Activity Monitor and search through
"All Processes" (select this from the pull-down menu) for anything with LifeAgent in it's name and "Force Quit" it. This should have the effect of removing the status icon. If this works then using Spotlight, try searching your Hard Drive for anything containing LifeAgent along with the name of the process that you may/may not have noticed in Activity Monitor.
When this rogue icon is visible, do you have any external HD's attached?
Hope this helps