Forum:Needle Worm: Send of Discard?

My friends and I are big fans f Needle Worm, but ironically enough, we've never noticed or paid attention to it's text. As far as we know, we've been treating it's effect as "sending" instead of "discarding," thus activating Penguin Knight's effect and similar cards. Since effects like Penguin Knight's activates when it is "sent," Needle Worm won;t have trigger it's effect, right? Or am I wrong?

Are there even any cards that discard from the deck excluding Needle Worm? We thought discarding only happens in the hand?

Anyways, Thank you!!