The keyword includes "Upd" for a reason. For decades, these films were considered basura (trash). Studios like Larry Santiago Productions and Prima Films (or "Pilipinas" labeled tapes) literally threw their master reels into dumpsters.

Here is the update (Upd) as of late 2025:

Before the 1980s, Philippine cinema was known for its "Golden Age" in the preceding decade, characterized by artistic masterpieces. However, the economic crisis of the early 80s shifted audience preferences. Producers realized that sex sold, and it sold well. To combat the waning ticket sales caused by the popularity of foreign films (specifically Rambo and Kung Fu movies), local studios pivoted to soft-core pornography.

This era gave birth to the term "ST" (Sex Trip) and "Bold" films. Initially, these films featured implied sexual acts and nudity. However, as the decade progressed and regulatory boards (like the MBTC) became more lenient, the industry pushed further, leading to the "Pene" (short for penetration) films. These were distinct from standard bold films because they featured actual unsimulated sexual intercourse on camera, though often filmed in a way that blurred the line between documentary and erotica.

By the late 80s and early 90s, the "Pene" trend began to wane. The influx of cheap, shot-on-video "Toro" films (hardcore porn sold on VHS) destroyed the market for theatrical "Pene" releases. Why pay for a movie ticket when one could watch harder content at home?

Myrna Castillo, like many bold stars of the era, eventually transitioned out of the limelight as the industry shifted toward action flicks and teen love teams in the 90s.

Her legacy today is significant:

For the uninitiated, the term "Pene" is slang derived from the English word "penetration," used colloquially in the Philippines to describe the golden era of softcore and hardcore adult cinema. Before the age of easy internet access, the "OT 80s" (Office of the 80s, referring to the decade) was the wild frontier of Philippine cinema.

While mainstream cinema gave us Nora Aunor and Vilma Santos, the midnight movie circuit gave us the bomba queens. Among these stars, one name resurfaces constantly in forums, vintage VHS collector groups, and Reddit threads: Myrna C. — more widely known as Myrna Castillo.

Upd (Update): As of 2024-2025, there has been a massive resurgence of interest in digitizing and re-watching these lost films. This article serves as the ultimate update for collectors, historians, and curious fans looking to understand the legacy of Myrna Castillo and her contemporaries.