She looks like she's wearing normal clothing at a distance, but soon the bulge around her waist and a faint crinkling sound alert you to what she is wearing under her pants. Samantha doesn't seem to have noticed and you decide to not say anything so that Samantha doesn't make fun of her.
Soon, your mom gets back into the car and sits down, ready to drive again. There's something different about her though. What was it.