How do I make object a little dark effect

hi,

I've made object (character / enemy) that walked to x, I want my object if I touch it, that object has the effect of flickering dark.

I've tried to make it by using flash behavior. but it was not flickering dark.

for example, in clash of clans game. if we touched town hall or any object, the town hall was issued a flickering dark.

Anyone else have any suggestions?

p.s : sorry about my english

I don't really understand what you mean by flickering dark, but if you are trying it give it an effect, perhaps the easiest is to create an animation for it. Than when touch, play that animation. If you are trying to just get it to flash, with a dark tint, another way would be to create the dark tinted image, than on touch, create that tinted object and have it flash than destroyed.