What is "Unsupported method 'FLAPON '"?

I found the following lines in my Squid (v2.3S2) cache.log this
morning:

--- start cache.log snippet -----

2000/04/22 10:07:31| parseHttpRequest: Unsupported method 'FLAPON

'
2000/04/22 10:07:31| clientReadRequest: FD 18 Invalid Request
2000/04/22 10:10:27| parseHttpRequest: Unsupported method 'FLAPON

'
2000/04/22 10:10:27| clientReadRequest: FD 17 Invalid Request

--- end cache.log snippet -----

I've never seen this before. What the heck does it mean?

Thank you.

*** Steve Snyder ***
Received on Sat Apr 22 2000 - 10:31:16 MDT