bobber

Short definition from Wiktionary

Noun

1. 1
   One who takes part in apple bobbing.
2. 2
   A buoyant device (frequently made of cork or hollow plastic) attached to a line so as to suspend the end of the line with the hook (and bait or lure) above the bottom.
3. 3
   A style of custom motorcycle with stripped-down bodywork and a shortened (or "bobbed") rear fender.
4. 4
   A person who rides a bobsleigh; a bobsleigher.
5. 5
   One who has a bob hairstyle.