after the Oversight Sendai, we went to face the good old imporved Abazigal. By the end of the battle (well, we finished him quite soon and so it could as well be the first few rounds after he turns to his dragon form)...a Greater Earth Elemental came to help us from nowhere. We didn't summon it, and after we past the Challenge four, sleeping for a day, getting triggers and contingency up again, we turned back to Abazigal lair, the Greater Earth Elemental was still there (so it's definitely not a summon).
Did anyone meet this unexpected ally before?

Abazigal casts Earthquake.

The spell description of Earthquake should answer your query.

ok, got it, so the last spell he cast was an earthquake. Good that we were high lvl enough to be not affected by the quake...guess he just wish we failed the save and dropped the weapons. The problem is though that the Greater Earth Elemental was still there after 24 hours. I've never used that spell since it's not party friendly.

thanks^^