Baby-to-Be Nicknames

DH and I are TTC. On Monday I took an opk and it was positive so we are doing a lot of baby dancing! Fingers crossed! We want to pick a nickname for our potential baby, rather than saying "It" because I hate that. So far we've considered Kiwi, Jelly Bean, Pickle, Jelly Kid or Catbug (Bravest Warriors, anyone?) and Squishy. We have names chosen for a boy and a girl but we aren't sure yet if we'll find out. I kind of like the surprise idea. Anyway, what are some nicknames you've used for your LO while pregnant? Any suggestions? Also I am a huge geek so anything Doctor Who/Harry Potter/Sherlock/Merlin or anything else nerdy is welcome ?