<a href="http://stars.astro.illinois.edu/sow/n6741.html" rel="nofollow">NGC6741</a> is quite small but also quite bright and various details are easily discerned. It has a somewhat rectangular or parallelogram shape from our vantage point and the skinny, somewhat linear structure around the center has a curved shape implying that it may encircle the star all the way around though we can only see the side facing us.

Kaler <a href="http://stars.astro.illinois.edu/sow/n6741.html" rel="nofollow">mentions</a> that the central star is unseen but it is clearly visible here and I do see it in the Hubble image he provided with his description. It is quite easily noticed in the f555w data even without sharpening. It is indeed invisible in the other two sets of data, f658n and f502n.

I don't know who called it the Phantom Streak or why it is called that. Most small nebulas like this don't receive common names. It's a cool name though so we may as well go with it.

Red: hst_08773_04_wfpc2_f658n_pc_sci Green: hst_07501_04_wfpc2_f555w_pc_sci Blue: hst_08773_04_wfpc2_f502n_pc_sci