Bene Scripsisti de Me.

"William of Tocco recounts a story, which he heard from Friar Dominic of Caserta, the sacristan of San Domenico...Friar Dominic, apparently, became curious about Thomas' frequent visits to the chapel of St. Nicholas in San Domenico before Matins. One night Friar Dominic concealed himself to watch Thomas in prayer. He saw Thomas elevated 'almost two cubits in the air,' and he heard Thomas praying fervently and weeping. Then he heard Thomas speaking to the crucifix on the wall of the chapel. The figure on the cross said, 'Thomas, you have written well about me. What reward will you have?' To which Thomas replied, 'Lord, nothing but yourself.' Tocco adds that at that time Thomas was writing the third part of the Summa on the passion and resurrection of Christ. It could very well have been the treatise on the Eucharist. To this day the friars of San Domenico point out the crucifix that spoke to Thomas in the chapel of St. Nicholas" This stained glass window is in the church of St Vincent Ferrer in New York.

Source: Lawrence OP on Flickr