In the dash where the clock is...the security "word: remains hilighted and the red "key" symbol flashes- why ?

It sounds like a bad connection on the battery, remove the cables and clean them. Also check fuse #6 and #8 in the under hood fuse block.

You can't do anything ,unless you have diagnostic computer . Check codes , program key etc.... Call a mobile lock smith or have towed to the dealer .

This indicates that the immobiliser is active!

You may have burned something up. Check with manufacturing codes, the rapid light flashing can be a code.

How would someone know what funny shape means

If you have no owners manual google dash board symbols

When you turn on the key you should see & know every
symbol on the dash
After the engine starts they all should be off or you got problems

Here is a fix >

Security and Immobilizer System Indicator Symbols Symbols & Tell-tales
These are Security and/or Immobilizer System Indicator symbols used by manufacturers. One of these symbols lights momentarily to indicate that the ignition switch is locked and will need the proper transponder-equipped key to re-start. The vehicle is immobilized otherwise. Green symbols will flash when the vehicle is immobilized.
If the symbol is visible when the vehicle is on, it indicates a malfunction in the security system. If the engine does not start with the correct key, and the security indicator remains on, the system may have a malfunction. You will need to contact your dealer in either case.
Keep the Symbol meanings with you!

Security lights. Is it a GM vehicle? It is normal when the key is out for the security light to flash

Usually on the passat, if the immobiliser is on, there is a yellow key symbol flashing on the clocks as you try and start it. Do the doors unlock with the remote key? If no flashing light and the key fob working, i would be looking at possibly starter relay. This is either located under the fuse box or under a plastic cover near the windscreen under the bonnet. (hood)

This is the factory installed "Security" light. It blinks to let you know that the security system is active, and to ward off potential theives. It's part of the factory anti-theft system. Also, it is a diode, and consumes virtually no battery power.
Normal condition; nothing to worry about.

Anti theft device malfunction.