If this card is Normal or Special Summoned: You can target 1 Beast-Warrior monster in your GY; this card's Attribute and Level become the same as that monster's, until the end of this turn. During your Main Phase: You can Special Summon 1 Beast-Warrior monster with the same Attribute and Level as this card from your hand. You can only use each effect of "Three Trolling Trolls" once per turn. You cannot Special Summon monsters the turn you activate either of this card's effects, except Beast-Warrior monsters.
Can only special summon monsters with similar attribute, type, and level as himself.
Three Trolling Trolls is the only monster with his combination of attribute, type, and level. So you will only be able to summon more copies of Three Trolling Trolls without the help of other cards to change attribute/type/level.
Three Trolling Trolls can temporarily copy the attribute and level of a Fire Fist monster in your graveyard. All main deck Fire Fist monsters are FIRE and most of them are level-3 or level-4 so copying those levels already give you a wide selection. Special summon a level-3 Fire Fist monster from your hand and make Brotherhood of the Fire Fist - Horse Prince.
Use DNA Transplant to change Three Trolling Troll’s type so you can special summon level-3 WATER monsters of the type you selected. The best type to select with this attribute and level are Sea-Serpent, Aqua, and Fish.