Question about an ability I’ve seen on yt

So I’m fairly new to the game currently level 23 but I think I’ve found my main with fiddle. Now I’m trying to learn the champ and I’ve seen people using this ability I’ve made a screenshot of here from time to time. From what I understand it’s hextech flash. How useful is this on Fiddle and what builds do you guys use in general or what is considered best build at the moment? I’m running domination tree with electrocute, cheap shot, grisly memento and ultimate hunter paired with axiom arcanist and transcendence but I’m open to suggestions!

So I’m fairly new to the game currently level 23 but I think I’ve found my main with fiddle. Now I’m trying to learn the champ and I’ve seen people using this ability I’ve made a screenshot of here from time to time. From what I understand it’s hextech flash. How useful is this on Fiddle and what builds do you guys use in general or what is considered best build at the moment? I’m running domination tree with electrocute, cheap shot, grisly memento and ultimate hunter paired with axiom arcanist and transcendence but I’m open to suggestions!