Bat in a box

This wondrous item may seem to be nothing more than a small innocent looking paper box wrapped up in pretty colors with a nice bow. But a successful DC15 investigation check will reveal otherwise. No checks are needed to find the small hand crank on its left side, which will instantly begin to turn if any creature is inside of its 30 foot sensing radius. The only way to avoid this is to either be in some sort of stealth (like invisibility or a DC14 stealth check) or to disarm it, which will require a DC18 tinkers or thieves tools check. After spending 6 seconds spinning, all while a small tune of “pop goes the weasel” is played, right at the climax of the song the top lid bursts open and a small satin bat bounces around on a spring that was used to propel it out of the box. After a single second to see the bat, the entire box explodes with three different types of grenades: fragmentation, tangler, and smoke simultaneously. The perfect gift for those goody two shoed costumes freaks.