What if a champion only had the ability to summon units?

When I say only able to summon units, I don't mean like where you revolve around your soldiers, I mean you LITERALLY can only summon units. I also don't mean like , simply because his units expire. I am thinking of a champion that has 3 basic abilities that all summon permanent units that can be controlled and used to attack, and for an ultimate maybe it could be where he goes INSIDE a minion,like a mech, and cannot be damaged until that mech is destroyed, or until it expired. The cool part about this is the mech could have COMPLETELY different abilities, that maybe didn't summon units.