Friend from Malaysia Bronies Society found this! I don’t follow official merchandise, but I’m sure I haven’t seen this anywhere else online (do correct me if I’m wrong here). It’s what the packaging says. They’re key chains which shine light when pressure is applied.
 
This photo was taken at the MPH outlet in Nu Sentral, a shopping centre in Kuala Lumpur, Malaysia. They’re priced as follows:  
Twilight + Spike = RM34.90  
Rainbow Dash = RM19.90
 
Also they were doing a buy one get one free special. Twilight and Spike both count as one, so friend got the Rainbow Dash design for free. However…seems like there’s no way to change the battery without damaging the key chain once they go out. :<