[Oh god they got Papyrus in on it? That's...concerning. For one thing, Sans isn't sure he's okay with Papyrus hanging out with Chara, even though things have kind of settled back into normal calmness. And for another, holy shit, he's gone up against Papyrus in prank wars plenty of times over the years and he has lost every single time.]
[Also he is never going to forget the screaming of thousands of plastic birds.]
[Actually Sans had to look up what a duck actually was. He gets them confused with chickens. Anyway.]
[Chara might duck when then leave their room next but it won't actually matter, because the real danger is on the floor. If they step on a small, hidden wedge on the floor...]
[...an entire twenty-gallon bag full of colorful duck feathers will be catapulted right into their face.]
4/12, late, stuck to their door, along with a single duck toy
[Also he is never going to forget the screaming of thousands of plastic birds.]
[Actually Sans had to look up what a duck actually was. He gets them confused with chickens. Anyway.]
[Chara might duck when then leave their room next but it won't actually matter, because the real danger is on the floor. If they step on a small, hidden wedge on the floor...]
[...an entire twenty-gallon bag full of colorful duck feathers will be catapulted right into their face.]