Bhagavad Gita 18.38

विषयेन्द्रियसंयोगाद्यत्तदग्रेऽमृतोपमम्।परिणामे विषमिव तत्सुखं राजसं स्मृतम्॥

viṣayendriyasaṃyogādyattadagre'mṛtopamam |pariṇāme viṣamiva tatsukhaṃ rājasaṃ smṛtam ||

That happiness which arises from the contact of the senses with the objects, which is initially like nectar but eventually like poison, is said to be Rajasic.

That which, at first, is like nectar, as the senses revel in their objects, but in the end acts like poison—that pleasure arises from Passion.

Our plain-language meaning of this verse is waiting for scholar review.