Change the behavior of black powder

[Mouse]

First, in small amounts (10u or less), make it nonexplosive.  It still sparks and burns and sets nearby flammable things on fire, but it doesn't explode.
Second, applying black powder to a tile makes a pile of black powder that will join into a line with other piles of black powder, similar to the behavior of salt and, IIRC, magnesium.

Keep everything else the same.

(I wanted to link an "educational" video but holy hell youtube's search is awful these days)