Alternate Monster Crystals??

[incupal2 0]

Sorry if the title is a little vague. I just have a question. So every time I go leveling, I bring with me a boatload of monster crystals that I bought from the Huntress as I think everybody does. Now, there's something weird that happens (not every time though) when I activate these crystals. They summon a more powerful variation of the monster in the crystal which is awesome because I can level faster that way. Is this a random thing or is there something you can do to make it happen more often (or all the time for that matter). Thanks!

 

[Arcanite 0]

It's called boss time. I don't know the exact time, but I guess it's between 8-10 pm (server time, ofc)

 

If you release a monster inside this time, it will, instead, summon the boss variation of the monster