Alright, I've been raising a Larvitar up to a Tyranitar, and as soon as it evolved into Pupitar, it takes a ridiculous amount of EXP to get to another level. I don't use an EXP share, I just place it as first, then fight until it faints, or I exhaust my armageddon stockpile of hyper potions. I got bored with this, then decided to level up some pokemon (a squirtle and a sneasel) and when they hit their 30's, it was a breeze to get them from their previous levels (14 and 21) to 40, infact, it took one of them much less time than pupitar to gain a level. Any explanation for this annoying phenomenon?