From my pond microforay: (Edit: the organism below is NOT the mystery organism. Follow the link below instead! I fail at making sense lately...)
The mystery organism is special with respect to this form of motion. That was a very massive hint.
Also, not this:
(Leander et al. 2001 Evolution)
The protist geeks among you better get it this time!
Macrocycles, flexibility and biological activity: A tortuous pairing
20 hours ago in The Curious Wavefunction