A plugin that lets you put any item in the suspicious sand or gravel
This plugins add two new crafting recipes to the game, one to make Suspicious Sand, which requires a block of sand and any other item of the game, to make a block of Suspicious Sand with that other item inside of it. The other recipe is the exact same thing but for Suspicious Gravel, which requires Gravel and any other item.
Enchanted items or items with custom names are not supported entirely yet, using any of this items in the recipe will cause to lose the enchantments, names and all extra information that item had.