Once per turn, during your Standby Phase: Take 1000 damage
Giving your creature spells offspring 2, which allows you to make a 1/1 token copy of the creature you cast, just increases the amount of potential for the first ability
Oh and thats not all, as Altaria ex also has a pretty nifty Ability which allows you to heal 20 damage from each of your Pokemon, once per turn, every turn
My best prediction is that it will also be one of the most valuable cards of the entire Sword and Shield era, right up there with some of the greats from evolving skies
If theres 6000 of each invention cards printed, its a good bet 95% of them are still NM, as compared to maybe 10% for Alpha
Even better, if you have an activated ability like a Rakshasa Deathdealer or a creature with outlast or monstrosity, you can use your mana on that instead of casting a spell and never give your opponent a chance to use his or her mana at all