nudibranch?

Help. Me and my husband are new to reefing, we started in January this year. We have found this little guy in our tank a few weeks ago and have asked our local very knowledgeable reef shop what it is but it has stumped them. Any help would be great

^ Top view ^ Bottom view What is this hitchiker? Looks like a fireworm due to the glass hair spines but its too short to be one and the belly looks like a suction cup type deal similar to abalones