When I was playing around with command blocks, I thought of creating custom fishing. I used /summon to try and find a fishing rod hook's entity ID, but couldn't find it. Then I tried stuff like @e[type=Hook], @e[type=Bobber], and @e[type=FishingRodHook], but couldn't get a correct ID. When you target everything, the fishing rod hook gets added, so why can't you target the hook itself?

Steps to reproduce:
1.Throw a fishing rod hook somewhere.
2. Do /say @e or /kill @e
3. Look in the chat and how it says "unknown".
4.Try and enter "unknown" into an entity selector, and see it not work.

Note: If this is only me, or this is intended, then sorry bout' this.