Increase the original ATK and DEF of all face-up Level 2 Normal Monsters (except Tokens) on your side of the field by 1000 points until the End Phase. Destroy all Level 2 Normal Monsters on your side of the field during the End Phase.
Rulings
Individual Card FAQs
If you Summon a monster after the resolution of "Thousand Energy", it does not gain the +1000 ATK, but it is still destroyed during the End Phase because that effect is applied to all Level 2 Normal Monsters at that time.
If you have "A Legendary Ocean" reducing Level 3's to Level 2, and the effect of "Thousand Energy" is applied, and then "A Legendary Ocean" is destroyed, the levels are returned to Level 3, the ATK/DEF bonus from "Thousand Energy" is lost, and those monsters are not destroyed during the End Phase.
A monster affected by "Thousand Energy" is not destroyed if it is face-down during the End Phase.
If a monster affected by "Thousand Energy" switches control to your opponent, it is not destroyed during the End Phase.
If a monster affected by "Thousand Energy" has its Level changed so that it is not Level 2 during the End Phase, it is not destroyed.
If you use "Cost Down" to make a Level 4 monster into a Level 2 monster, Summon it, and use "Thousand Energy", during the End Phase you can choose which effect happens first, so you can restore it to Level 4 first by ending "Cost Down"'s effect, and then it will not be destroyed by the effect of "Thousand Energy".
Spell|
Normal