Id. Help with a new critter, friend or foe?

[Noodles]

Hi, tank been set up for few years now, a new critter has come along, about a cm long like a flat worm with two antennas, almost slug like, has a brown spoty back, not a bristle worm. Is it a sea hare? Is it best to get rid of? It's in a reef tank with corals
Thanks in advance,

 

[AbsoluteFaye]

Someone else posted the same creature last night! I'm very curious to know what it is. It's comical and cute.

 

[AbsoluteFaye]

Could be dendrodoris. Does it look like example "H"?

 

[Noodles]

My puffer just 'pecked' it of the glass and as it was falling in went into both my clowns mouth then back out. Then my damsel ate it and spat out. I thought it was a gonna when it hit the bottom, but he/she just scurried of.

 

[AbsoluteFaye]

Guess he doesn't taste good!

 

[Noodles]

Yeah deffinately h, thanks for you help, another one has popped up now, I just upgraded my lights yesterday, wonder if that has anything to do with it. Any idea whether its good or bad?

 

[Noodles]

Thanks for your help!!!