Can only Special Summon itself when you control no monsters.
The free Special Summoning and level modulation effect make this card great for making Synchros. Paired with a level-2 Tuner you get access to level-7 and level-8 Synchros, which have the widest range of generic Synchro monsters.
Special Summon Primitive Butterfly and increase its level by 1. Then use Insect Imitation to Special Summon a level-7 Insect from your deck, letting you Special Summon Metamorphosed Insect Queen.