**Adjust the Dark Spark in some manner to make it more satisfying to get/stand-out**
(I am the donor the Dark Spark was made for, for the sake of clarity)
The Dark Spark has become a bit of a relic in Calamity Mod due to balance changes, mechanical adjustments, and et cetera. While it's still a very visually appealing weapon, it being how it is currently holds it back, and I'm of the belief that it needs something of a facelift. Dark Spark as is, while it's definitely an interesting item that plays with the idea of being a reverse last prism, inherently has a number of mechanical issues as a result;
-It's extremely slow to get to the point where it's a technicolor light show, hampering the enjoyment of using it (17 seconds total for it to go from black to rainbow, as opposed to the Last Prism's 3.4 seconds going from diverged beams to single laser)
-Once it gets to that point, it drains mana extremely fast, requiring some form of mana flower to maintain - which inherently nerfs its damage due to mana sickness as well as being extremely resource hungry (common of all prism weapons but it taking 17 seconds makes this especially egregious)
-The only boss it could reasonably be brought to is DoG, due to lying after every other boss in the tier and DoG itself being a progression wall that has an explosion of new items beyond it that rapidly cause it to be outscaled and having an extremely small window of use
-Due to piercing damage being halved, as well as having a specific 85% damage nerf against DoG and DoG now reducing all non-head damage a great deal, it's no longer as good of an option as it used to be for DoG, arguably being outclassed by the much cheaper Phantasmal Fury, which can be made after killing Poltergast a single time as opposed to Dark Spark's minimum 2 on Expert
-Compared to the excellent sound design of Yharon's Crystal, the swooshy lightsaber noises the Dark Spark inherited from its predecessor could definitely be improved upon
All these things combined it's a very pretty toy that disappoints people when they finally do manage to pick it up, and while mechanically it still can do what it used to do, it feels a lot less cool now that Calamity's matured in both mechanics and aesthetic. The item is almost four years old now, and I think it's in need of a meaningful change.