Monstrump Egg.

Monstrump Egg: A strange egg or egg-shaped carrier pod that contains a Mini-Monstrump (Trump-creature) inside it,  it is usually transported to the households of humans and left for some place in the home for said human to find it. The egg variant hatches to let the Mini-Monstrump out while the carrier pod opens up and the Mini-Monstrump leaps out of it and greets the human as a whole, in addition to this the Mini-Monstrump will come with an instruction book that teaches you how to take care of it.  It is done in the vein of one of those 'electronic' pet toys and virtual pets in general such as the Tamagotchi,  and you have to make sure it stays happy.

The main objective is to look after and take care of the Mini-Monstrump, play with it,  nurture it, feed it and make sure that it remains happy and doesn't get lonely or upset.  It is basically akin to that classic scenario where you have to look after something like an egg and treat it like it's a real child.  What kind of Monstrump your Mini-Monstrump turns out to be is a mystery since it can be any one of the themed Mini-Monstrumps and sometimes has a varied range of evolved forms it can become depending on how it is raised.  

As the bond between the human and their new bundle of uhhh...orangeness grows,  that human will like they can relate to them, in addition to this they will slowly but surely become a Monstrump themselves, albeit a cuddlier variant of one to be either a father figure or an older sibling to them, and there is MC involved as well.  There may be twinning involved if the Mini-Monstrump requires someone to be turned into their identical sibling.