Did anybody realize these strange trades, too?

http://de.advfn.com/p.php?pid=staticchart&s=TX^EOG&p=0&t=37&vol=1

It seems like somebody or something - a bot? - is throwing 500 shares into the BID in an interval constant in time.

So far so good, but for what reason?

Any ideas?

Cheers and have a good day,
Neo