It is a odd shape, but IF it is a sponge no issues.... Watch it over the next severl days to see if it is detererating. They are common hitchhikers that show up..... As to exposing to air, yes even short air exposes kills them. The slightest bit of drying out of its tissue often will do in the entire sponge. But their spores can survive in the air. Many Reefers end up with many colors of them after a few years from the spores on the live rock..... I have the common white. red, blue, green, brown and yellow ones...... another of the little treasures of this hobby we see in time.......
Ohhhhh by the way....... Welcome to the Boards!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!