hammer coral-what is up with this tentacle?

[melonheadorion]

just did a water change, and while the tentacles were a little retracted, i noticed this tentacle looking a little wierd. dark area on it, and looks defalted. the rest of the coral looks completely healthy, so i am not too concerned, but since i am newer to coral, i was curious as to what this is/the cause/anything to watch for or be alarmed with?

i zoomed in as much as i could

 

[vetteguy53081]

Curled and Not abnormal

 

[DrZoidburg]

Two things come to my mind. 1 maybe bacterial infection causing it to shrivel up. 2 maybe its a sweeper tentacle making its way out.