You are confusing an activity with an entity. There are things that cannot be done but we have evidence that they cannot be done. You start by saying not existing and then switch your meaning to cannot be done.
There is no evidence for or against Mod's Maximal being, only philosophical arguments.
So you point about Mazdas is about doing something (a verb), rather about an entity's (a noun) existence.
I can provide proof that it is possible to draw a King of Hearts from a standard deck of cards. Can anyone provide similar proof that an MGB could exist?
Here Mod draws the distinction between doing and being.
I question the claim that it is possible that a maximally great being exists, and want to see the argument, along with the evidence which confirms it is possible.
As far as I can see from this post Mod is clarifying he is describing an entity, not an activity.
I guess I can think of a whole heck of a lot of things that you can't prove are possible.
My understanding is that you were follwing Mod's point of an entity, here.
Here I ask for an example of an entity (following on from my understanding of Mod's point and your reply).
Stacking ten Mazda sedans on top of each other. Eating four bananas, three cherries and one small mango in exactly 4 minutes and 23 seconds. Singing three verses of Fiddler on the Roof while standing within four meters of the Grand Canyon....
These are activities, rather than entities.
Frankly the OP talks about an entity from the outset. It is not until you post about Mazdas that there was a change from a maximal great being to someone doing something.