Board Thread:General Discussion/@comment-27907368-20160412010659/@comment-26242189-20160508123912

True, but whenever a monster sees you, they can't tell your human (RG-01+02, Batty and Catty, Gerson, ETC). Sans can on sight, as well as Undyne. Papyrus cannot. Alphys can. ETC.

Also, this shows that Temmie has seen a hooman before :P