The Laboratory is a place where the player can transform his or her fighters and pets into different ones of the same quality. For example, transforming a Rocky (Basic Fighter) will result in another random Basic Fighter. the player cannot receive a Legendary Fighter from transforming a Junior Fighter.
The laboratory is unlocked at level 31
Since the player needs to upgrade his or her fighters or pets with equivalent +0 fighters or pets, this area is especially helpful in facilitating the process.
In order to upgrade a level +3 Rocky to +4, you can use two Basic Fighters that are not Rocky. In order to do so, the player must transform them continuously until they both become Rocky. From there, the player can use those to upgrade Rocky to +4.
The process is identical to pets. Level +0 pets can be transformed and fused.
Information about fusion can be viewed on this page:
The first transformation of the day costs 1000 Gold. Every time the player transforms a fighter or pet, the cost increments by 50 gold. So the second transformation costs 1050, and the third transformation costs 1100 Gold.
This cost resets at the end of each day.
Transformation events make it so the cost does not increment.