Not a Crocus!

A sternbergia, perhaps Sternbergia sicula but the taxonomists argue over the names of these bright yellow flowers in a genus more closely related to daffodils than crocus.

From daffodil-like bulbs the flowers emerge very quickly in early autumn. You can see the beginning of daffodil-like leaves too while the flower is borne aloft on a green stem, another difference from crocuses. Easy to grow in a free draining soil in full sun, being native to the southern Mediterranean, they like the heat, flowering best after a hot summer.