User blog comment:Atanchan/Lumi, the Poro Knight/@comment-7709681-20140815192136/@comment-24464243-20140815210350

Yep, a big ol' fat ball of fluff! Though not too big, since Lumi herself is a Yordle who ended up in the Freljord.

Also, for reference, Glacial Prison has 675 more range than the ultimate's reach in either direction, and there's stuff like Shaco boxes and all of Annie's abilities that can disable her for non-ultimate solutions. That's why it's channeled; not all team composition wills have a way to stop it, but there's far from zero champions that can't drop a disable on her from outside of its range.

Also, in a way, it's sort of like Amumu's ultimate but with more gameplay around it. Lumi has to actively stick the enemy team to keep them under its effect - since they, not Lumi's team, have to be under its effect to protect her team mates - and stuff like dashes and speed buffs are still available to the enemy team as a whole since she can only effectively lock down one target for most of the ultimate's duration. While enemies can still cast spells under the effect of Amumu's ultimate, Song of Serenity has a similar note where high-ranged champions can skirt around the radius and still provide poking. Not to mention should Lumi's carry be lagging behind, they're still entirely vulnerable to, say, Kha'zix leaping out of the radius and nuking the carry to nothing.

That's why I based the cooldown and range off of Curse of the Sad Mummy, with a slightly lower cooldown early to make up for the lack of damage and the slightly lower duration. It's a lot more nuanced than the instant AoE entangle, and on later ranks it's on a slightly higher cooldown anyway.

Thanks for the comment!