I think it would read better if it said "Mechanical Horror gets +2/+2 for each Equipment attached to it." This sort of ability is usually white or red, however; see Loxodon Punisher for the same card but costing .

Eh. I dig the fact that he's forward compatible, even if new players may not "get it". Listen to me, scatting with beat talk. Take that Daddy-O!

Also, the fact that Loxodon Punisher exists would get me to increase his casting cost to . Commons shouldn't be as good as rares, and this feels like a logical common ability. But, yeah, there may be a mechanical tie missing in color. Should he give +3/+0? That at least feels a little more Nim-mish. And you probably won't need the toughness anyway, since one or two equipment will probably give him +1 to +4 toughness.

Hm. This cardset seems to include Fortifications (which can't be attached to this), but not yet anything like Connectors (which can).

at common, you would probably only want it to get +1/+0 or +1/+1.
You could give it a second ability that attaches equipment/connectors to it from the graveyard to make it feel more Black (would need to cost a bit say ) though that may up the complexity too much for a common.

Camruth. You are onto something.

I was working on an "Assemble" mechanic similar to Connector but I haven't found the precise wording I want to work for it. That was the idea though, that this card would get pumped for each thing it was assembled from.