What sort of monster would be drawn by magical energy?

[CoI]

My players will soon be coming across a secret magical school/library and I want them to have a quest for the party. I was thinking some sort of monster has been drawn by the magical energy swirling about that the party can slay for them. But I'm drawing a blank as to what kind of monster that could be. I'd prefer non-humaniod, but I'll take what I can get. CR can be up to 10 or so. I'd also like it to be mythic, but that's optional. Any suggestions?

[Kazaan]

How about a magic sketchbook that summons manifestations of the drawings contained within. It literally "draws" magic creatures similar to a summoner's eidolon (it might even be an old summoner's spellbook where he used drawings as the basis for his recorded spells). For bonus points, make the sketchbook an intelligent item.

[Plausible Pseudonym]

Scourge of the Godclaw has a CR 12 ooze called a Spellgorger that engulfs spellcasters and then parasitically uses their spell ability as its own. But it only feeds off spellcasters, not magic items or spells already in existence.

[Buri Reborn]

I've seen reference that dragons can smell magic.

[Val'bryn2]

Devourers can be attracted to the magical emanations,

[bigrig107]

There's a Ravener in the Mana Wastes that's feeding on a Mana Well and attempting to become a mythic Ravener.
Perhaps your font of magical power has attracted another dragon and its minions?

[Protoman]

"What sort of monster would be drawn by magical energy?"

Why the very worst kind!

Dangerous.

Disgusting.

Kills without remorse or question.

Defiles corpses and its belongings.

...ADVENTURERS!

[Amanuensis]

dweomercat

[CoI]

The dweomercat is PERFECT! Thanks everyone!

[CoI]

Now what mythic abilities would suit it I wonder..?