Spazmatism7
Plantera
Soon I am going to redo the attack pattern and put more details in.
This version of the boss is outdated. It will be different in the modWait... The summon for this boss requires you to get 27 of every fragment. Getting 20 of each fragment is bad enough for the Celestial Sigil. I think the boss looks pretty cool though.
The summoner one is kinda OPI had an idea for some new drops from Galactic Peril: a few accessories that when equipped change the set boosts given by the armor.
Summoner: Galactic Summoning Seal
New set boost: +13 Summon Slots, +10% summon damage, +75% knockback
Ranger: Universal Projectile Insignia
New set boost: +35% Ranged Damage, 10% chance to not consume ammo, 5% chance to create ammunition per enemy hit
Mage: Otherworldly Magic Insignia
New set boost: +25% Magic Damage, +20% knockback, 1% chance to refill mana per enemy hit
Melee: Astronomical Warrior Crest
New set boost: +10% Melee damage, +10% critical hit chance, Enemies struck have a 1% chance to drop Nebula Boosters