Answer:
My first is in ocean but never in sea. My second's in wasp but never in bee. My third is in glider and also in flight. My whole is a creature that comes out at night.
They don't forget.
These animals hang out in the mist.
What has a brown coat, a long tail, and lives in house or shed but most active while you're in bed?
A spent round or a slimy critter.
When you take away the whole from me there is always some left.