Pichu

Pichu gets +1/+0 as long as you control another creature.
{t}, Pay {e}: Pichu deals 2 damage to target attacking or blocking creature and deals 1 damage to itself.
{t}, Pay {e}{e}: Sacrifice Pichu, search your library for a red and white Mouse creature card with converted mana cost 5 or less, put it on the battlefield tapped, then shuffle your library.