Forum:Psychic Snail Query

I was looking over my Psychic deck, and going over the cards, and a question occured to me, the way I read the card of Psychic Snail it is plural when it talks about Battle Phases. I was wondering if I pay the 800 Life Points and target a Psychic Monster, does that Psychic Monster gain the ability to attack multiple times as a permanent feature, or does it only last until Psychic Snail is removed from the field, for example when you Synchro Summon Junk Warrior he gains the attack of all level 2 on the field, that stays permanent even as the Level 2 are sent to the graveyard. Does the same situation apply to Psychic Snail.

ie: Psychic Snail is on the field, and I tribute summon Storm Caller, I utilize Snail's effect and pay the 800 Life points targeting Storm Caller does he gain the ability to attack multiple times in the battle phase for just that turn, and then I have to pay the cost again my next turn, or does it stay permanent without the cost, either till Storm Caller is removed from the field, or Psychic Snail is removed from the field.