Prior to the ascension of Spearthrower Owl most of the contact between Teotihuacan and the Maya lowlands seems to have been strictly trade-related - a situation that changed quickly after Spearthrower Owl came into power. One interesting question that has yet to be answered is why this change took place, why trade-relations evolved into more aggressive interaction. Four years into his reign, we have what has been termed "the entrada of 378" - the military presence of Teotihuacan converging on the Peten region and beginning the Teotihuacan New Order. There isn't any record of Spearthrower Owl himself making the journey into the Maya lowlands, but he is fully represented by his general and a Lord of Teotihuacan, Siyah K'ak'.

Under the direction of Spearthrower Owl, Siyah K'ak' invaded the city of Tikal deposing the Maya king, Chak Tok Ich'aak, and installing the son of Spearthrower Owl as king (Yax Nuun Ayiin I) in September of 379. This Teotihuacano Dynasty of Tikal was to rule the city for over 150 years, only coming to an end when Spearthrower's descendant, Wak Chan K'awiil was defeated and sacrificed by Sky Witness of Kalak'mul. But not even that ended the prestige of the dynasty - in 695, after Jasaw Chan K'awiil of Tikal defeated Yuknoom Yich'aak K'ak' of Kalak'mul, a revitalization of the Tikal throne was celebrated on September 14th, 695 - a date chosen not only to celebrate the recent victory over Kalak'mul, but also chosen because it coincided with the 260th anniversary (the 13th K'atun-anniversary) of Spearthrower Owl's death. Tikal was not the only city affected by the reach of Teotihuacan - Uaxactun, a satellite city of Tikal, was also defeated and it was there that Siyah K'ak assumed the kingship, maintaining close ties to Tikal. Rio Azul and Naachtun also felt the power of Teotihuacan and one ruler of Naachtun describes himself as the yajaw (vassal) of Spearthrower Owl.

There are several intriguing references to Spearthrower Owl who is usually designated by an owl armed with shields, darts and the atlatl. The Marcador from Tikal seems to be a totem dedicated to Spearthrower Owl - designed in a Teotihuacano fashion and inscribed with an account of the entrada of 378, it has, located at the heart of its feathered medallion, an owl armed with an atlatl. Spearthrower Owl also figures prominently in the text and it is within this text that we are given his ascension date in 374. An interesting addition to that text is a damaged portion which might indicate that Spearthrower Owl married a lady of Tikal. Included in the burial of Spearthrower's son, Yax Nuun Ayiin I - Burial 10 at Tikal, are several pottery vessels, one of which bears the legend 'the drinking vessel of the son of Spearthrower Owl'. Stela 31 of Siyaj Chan K'awiil, Spearthrower's grandson, bears a small medallion with the Teotihuacan emblem of owl, shield and spears and also includes reference to the death of Spearthrower Owl.

With the city of Teotihuacan standing silent, these brief Maya glimpses into the reign of a Teotihuacano king are invaluable and thought provoking. Why would the Teotihuacanos suddenly revise their relationship with their Maya neighbors from trade relations to overlord and vassal? Did familial ties continue after the death of Spearthrower Owl between Teotihuacan and Tikal? One source mentioned the possibility of Siyah K'ak being a brother to Spearthrower Owl - was that the reason behind the invasion of the Maya lowlands? To relocate one brother and protect the Teotihuacano throne for another? Whatever the reasons, the entrada of 378, under the direction of Spearthrower Owl and his general, changed the tone of the Maya lowlands and influenced following generations.