From Shadow Dragons to Shadow Bears

[FlourescentKing]

Has anyone found a way to tone down the Shadow Dragon template to apply it to other creatures, for example, bears or manticores or other lower-CR monster? I'm looking for some sort of spreading corruption-esque condition that turns the creature into its equivalent of a Shadow Dragon....

[DracoKnight]

Has anyone found a way to tone down the Shadow Dragon template to apply it to other creatures, for example, bears or manticores or other lower-CR monster? I'm looking for some sort of spreading corruption-esque condition that turns the creature into its equivalent of a Shadow Dragon....

Yeah, pretty much do everything that the template has you do - except instead of a breath weapon, replace the normal damage the beast would do with necrotic damage.