Oh no. I've just realized what I've done.
Liam said he was thinking about cake. That's an odd thing to be thinking about, and quite possibly not what he was actually thinking about.
I only had him say cake because it seemed like an amusing option, but now we are presented with a very valid question that I honestly had not anticipated:
"Is the cake a lie?"
I'm so sorry.
Also, since I don't assume everyone in the world reading this comic knows everything, including popular memes from... Wow, 2007?
Anyway, "the cake is a lie" is a line from Portal, a video game in which you are promised the reward of cake for performing tests by a possibly treacherous artificial intelligence.
It is also possible you never receive any actual cake in this game.