The bane of the parent's wallet. Also, a pretty effective commercial.
Basically, this falls under one of two categories: girls' toy or boys' toy.
The girls' toy will show the girls all the accessories that come with their doll (sold separately of course), and all the awesome outfits. Normally, we'll see two or three girls talk about how fun it is to do their doll's hair. Expect pastel colors, rainbows and twinkly stars. Any mechanical or electronic feature will be attributed to magic or claimed to be real and natural.
The boys' toy will show the boys all the awesome battle upgrades that come with their action figures, and all the sweet armor. Then we'll see two or three boys play with the toys by having the action figure shoot a plastic missile into a bunch of clear blocks (because, as you know, the small, clear block is a household necessity). If the character's enemies are available, they may be substituted for the clear blocks so that those can be advertised as well. Again, each sold separately. Expect an Overly Cool Play Space featured. Also expect the boys terrorizing parents and siblings withsaid toys. Expect loud voice-overs, flashing visuals and quick edits.
Expect a migraine if you have to watch too many of them.
Batteries not included, some assembly required.