New Summoner Spell or Item to counter mobility?

If Spell: Ensnare- launches out a projectile at the target, rooting it for ~1.5 seconds. Range: ~700 CD:~2 minutes

Item: Scepter of Damnation Cost: 2900g Build: 860 g Blasting Wand 820 Fiendish Codex Stats: +80 AP +10% CDR +20 MR [Damnation] Unique Active: fires out a damned projectile at a target enemy, slowing them by 20% for .5 seconds, then rooting for 1.5 seconds and silencing them for 1 second. Cooldown: 90 seconds (Range:600)

It's a point and click root, but point and clicks are needed against assassins