Board Thread:General Discussion/@comment-28128661-20160404143233/@comment-5956954-20160418065318

GetYourFix wrote:... Do you think Alphys mentioned it to sans? Or was she a total steel trap about what went wrong with DETERMINATION? There are a few ties between sans and Alphys (here's looking at sans and the dogfood...).

Flowey also has a hatred of Smiley Trashbag (here's him talking about sans) because sans has made him reset so many times. I think Alphys may have mentioned the vessel to sans and sans may have connected the dots between anomaly and a sentient flower thing.

We operate in a timeline where Flowey reset and waited for the formula to change because he was bored. So, sans may know of a sentient flower existing and wants us to know that its been talking to his brother. I mean, come on - how could what he's describing be an echo flower? And I believe sans has the instinct to search for what is messing with his brother... Hmm...

All speculation. ^^ Though, I am a bit more interested in seeing if this helps determine how Chara came back to haunt us. Sans is probably 50/50 with it. He either lied or was ignorant. The Sneak attack supports the ignorance, somewhat, because if Alphys told him, Sans would have bunny eyes, and the fact it is an anomaly to him to be talking to frisk about it, someone new to him, supports the fact he probably knows in some way. Would make sense if Alphys told him, but that would give him access to "the truth." He probably knows already but kept it a secret, considering his scientific background. He might know from an off-screen encounter of Flowey like most AUs' portray it. Maybe he knew from the lab cameras. Afterall, Alphys was in "the bathroom" and when we backtrack we don't see them again until the fight with EX.

We will never know. Spooky. Alphys telling him and Sans learning the truth would make more sense imo, but as I said before, Alphys probably didn't know the flower was malevolent and didn't give Sans a reason to care much as he probably connected the anomaly and that together, as you said, or maybe she did, but you know, it takes murdering nearly the entire underground for Sans to lay a bone on you.

So yeah, all speculation. That's why i am waiting half a year until Toby Fox reveals everything. He will be proud to see threads and discussions like these.