[quote=@LunarStandard]
<Snipped quote by Scarifar>

I would say maybe bump its original ATK down to 1600, and make the 300 ATK gain temporary for the turn you use the effect. It's a Breaker with an unconditionally better effect at the cost of being a turn slower, and I think the attack score should reflect that.
[/quote]

man, soon you'll be putting me out of a job.

[quote=@Scarifar]
Name: Breaker of Endymion
Level: 4
Attribute: DARK
Monster Type(s): Spellcaster / Gemini
Effect: 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: 
[list][*]Once per turn, you can destroy 1 Spell/Trap card on the field, and if you do, place 1 Spell Counter on a face-up card you control that you can place a Spell Counter on. If this card destroyed a Spell/Trap card this turn, this card gains 300 ATK until the End Phase.[/list]ATK/DEF: 1600/1000
[/quote]

Based scar reminding me I should probably make a separate section for Gemini Monsters. This version be accepted.