rock on, my guess for the box would be a lock of hair, cus its just cliched enouph that i dont think mandark could resist, and that would suport Tud Russle's theorty about Otto havin a girlfreind, which could also come back for a subplot were that puts a splinter 'tween' Otto and Dex.
Or Maybe Mandark sent a note too, saying that If you want Bellosom back, go bakc in time and rescue DeeDee.
posible, and it would also add some interesting twist, such as having another time squad come in to stop Otto from messing with the past, or even have their timesquad get sent (we are working in 4d after all), and have a big Tud Russle vs Tud Russle battle.
As far as why mandark would deleiver it to Otto as oposed to Dex, the answer is most likely ease. Dexter, and most likely his parents know that Mandark is responsible for Dee Dee's death, and I dont think they would take a package from him directly.