This card is treated as a Normal Monster while face-up on the field or in the Graveyard. While this card is face-up on the field, you can Normal Summon it to have it be treated as an Effect Monster with this effect:● The original ATK of this card becomes 2100.
Summon it once, end your turn, your opponent turn happens, once their turn is over and it's back to your turn don't summon anything and instead click on your Gemini and it will ask if you want to normal summon it, click it and it will have its effect.
I think it sucks cuz you spend a Normal Summon just to get him 2100 ATK. Even if you use Cry Havoc, it's like you tribute 1 monster to summon a 2100 ATK, the only difference is that you did not send anything to the Graveyard. So why not just use a lvl 5-6 monster with higher attack or some kind of equip... Except if you figure out something that has double benefit.