It’s kinda sad in my opinion

The theory states that when Mario was young he had a pet turtle, until he lost it and didn’t ever find it again.
Years pass as he has become friends with Princess Peach but Bowser who has grown up into, bowser. Still thinks Mario missed him, but since he never gets Mario’s attention
He decides to capture Princess Peach to get Mario’s attention again, but because of how Mario reacted Bowser had fight him

And since then, they’ve been enemies
Pretty cool right?

I believe this now

It kinda makes sense

How did bowser get into the mushroom kingdom
And what turtle is yellow with a spiky green shell

Some type of turtle I suppose