Central Concept: Mount Champion

No, not a mounted champion. A mount champion.

Basic idea is as follows: Tank/Support with an Ult that allows interaction ala Thresh's Lantern with allied champions. Upon clickin' the ally mounts up. While mounted, damage is split between the two champions with the mount taking a larger share as the Ult is leveled up. AoE attacks are only applied once as they effectively count as one unit while the Ult is active. The mounted champion is considered Rooted, but can otherwise use their auto-attacks and skills while the mount champion can move freely. No idea how long the mount effect would last, but I suspect making it last indefinitely would be OP as balls.

Any thoughts on what what you guys would like the rest of the kit to look like? Any preference on what sort of critter the mount champion might be? Griffin? Dragon? Some kind of mythical horse critter? A giant Yeti akin to Willump? Battle walrus?