Tenho certeza de que isso é Espécie II
After their return, the three astronauts - Ross, as well as Dennis Gamble and Anne Sampas - are examined by the space agency doctor, Orinsky, and quarantined to prevent them from engaging in sexual activity for ten days. However, at a fundraiser honoring the astronauts, Patrick quickly disregards this advice and makes out with a woman referred to as the Debutante (Lindsey, in the Novelization) in a lounge (his fiancé, Melissa, claims that he is resting, so she may not be aware of his infidelity). When he is called to give a speech, the Debutante/Lindsey invites him up to her room to have sex. After making his speech, he visits her room and finds her and her sister (actually her friend Claudia, in the novelization) both waiting for him. Patrick then has sex with the Debutante/Lindsey, then her sister/friend. As Patrick has sex again, the Debutante/Lindsey undergoes an accelerated pregnancy; within minutes, her stomach bursts open to release a newborn hybrid of human and alien DNA. This seems to sequenize with the alien DNA in Patrick as he sprouts tentacles, which the sister/friend notices; Patrick continues having sex, despite her pleas, leaving her to the same fate (which is never seen).
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Atenção, este link é muito NSFW devido ao PG: 13 nudez e efeitos de criatura.