Some time later, Professor Rossa discovered a secret passageway inside his own house, which connected him to a subway, a place to which the program moved for a few more seasons, leaving the first set.

In it, "Professor Rossa" sought to teach viewers (children and their families) interesting features of the animal world, for which he drew pictures, presented pieces of documentaries, and traveled to places where he could observe flora and fauna, or also the culture of other countries.

The humorous touch of the program gradually increased over time with the incorporation in 1985 of "Guru-Guru" (Francisco Ossa and later Claudio Moreno), and then in 1991 with "Don Carter" (Juan Alcayaga), the postman.

[4] Parallel to this, Arenas participated in other programs of the station, no longer in the role of Professor Rossa, but as himself, as in Maravillozoo, a cultural family oriented show with contests and fauna trivia, co-conducted by Javier Miranda, and sharing screen with Claudia Conserva, Coco Legrand and Yolanda Montecinos.

In 1999 he received the "Doctor José Tohá Castellá Award", recognition of scientific and technological dissemination, from the Ministry of Education of Chile.

[8] Since the first semester of 2012, Iván Arenas has been a frequent guest on the program Mentiras verdaderas on La Red, where he appears in the "uncensored" humor specials broadcast on Fridays.