Strange slug type invertebrate found today in tank

[Jhf3488]

Hello. I found a strange sluggish invertebrate in my tank today. I haven't added anything to my 29 gallon tank in months and it seemed to come out of nowhere

The size is about 3/4 inch in length and 1/4 inch in width. I shot a quick video if that will help identify it. http://www.youtube.com/watch?v=DFeWCMfo3R4&feature=youtube_gdata_player

Please let me know if you can figure out what it is and if it should be considered harmful to my reef

Thanks

[William]

the video
DFeWCMfo3R4

[Cliff]

I can't see your video as I'm at work right now, but have you taken a look through the pics and links in the below yet ?

http://www.aquaticcommunity.com/aquariumforum/showthread.php?t=89508

[kaybee]

Perhaps a stomatella.