Oscars ime, are all bark no bite... unlike alot of other cichlids. my bets on the aggro texas as well.. And that kinda aggression/hideing doesn't usually stop until one fish is dead.
i'd be shocked if it was anything other than your texas, nice tank - but IMO oscars just can't hang with the more slender bodied cichlids, especially one with the fighting potential of a T
i think is just stressed from being chased around in the tank, and it just lodged it self there to hide from its enemys.If it were butt kicked it would look worst then a couple of rip fins