This is a Vinyl figure.
They're actually called "Vinyl Figures" rather than naming them by the size as was usually done. (It seems odd to not have a line name, but) Anyway, here's Boom Knuckles mint in his cardboard...tray? The "5" down there is boasting "5 points of articulation", which, for a figure of this size isn't actually a whole lot. Plus, with his spikes the way they are, his head, while articulated, will never move much. His expression is kind of strange as well, he doesn't particularly look that normal or cool with his mouth open like that.
The packaging is terrible!
The figure is almost entirely exposed, and it has tiny fragile legs with the joint at the hip--where he is tied down. How many of these are going to be scuffed, broken or dirty before the consumer actually gets to them? No one is going to want to pay over 15 dollars for a filthy broken figure. MIB collectors will note the figure can gather dust & is unable to stack.