Talk:Laboratory/@comment-26156185-20150301140016/@comment-25856498-20150301140548

It says there in the trivia, although a particular troop/spell might be upgradeable at a particular Lab level, it will not appear as upgradeable until you unlock the said troop/spell.

You can upgrade the Rage Spell to level 2 in a level 3 Lab, just that 99% of players have at least a level 4 Lab by the time it finishes.

Similar things go with the Lightning Spell, Heal Spell, and Jump Spell.