Help with I.D. please...

[Browarican]

I have no idea what this is but it sort of looks like a snail with no shell... It's clear and has a little yellowish dot in the thickest part but is moving pretty quickly along the glass...

 

[Rob&Gab]

It's a type of flatworm . If I am correct looks like the type to eat algae

 

[Browarican]

Is it bad or can I ignore it?

 

[bmoore92]

+1 on flatworm. Google flatworm reef hitchhikers.