A concept, idea, project, etc. that is so confusing, it leads the habitual pencil biter to skip biting the unfortunate number two, and go straight to eating it.
"Hey, y'know this question's a real pencil-eater, it's been stumping me for weeks!"
"This project's such a pencil-eater, you mean to tell me I need how many sources for it? I can't even find one! Who wrote this textbook anyway?!"
"Man, adobe choosing to trick its customers into a year long subscription sure is a real pencil-eater! It's like they wanted a lawsuit or something!"
Carry + parasite. An mmo player who not only needs to be carried all the time, but is an active burden to other players. Constantly dying, distracting the team and contributing nothing.
"Bro I was running this mission with a rando squad and ran into this total carrasite! Bro needed constant reviving and just kept running around, I couldn't focus on shit! Eventually I just had to let him go man, wasn't worth the mission."