We describe a rare case of ocular surface squamous neoplasia (OSSN) with intraocular spread after excisional biopsy which presented as a postoperative anterior chamber (A/C) opacity, initially thought to be a hypopyon. A 60-year-old female with history of a right (OD) conjunctival mass involving the cornea, surgically excised and diagnosed as OSSN, presented 2 months postoperatively with an A/C opacity concerning for infection. The patient was prescribed prednisolone acetate and ofloxacin drops postoperatively; topical chemotherapy was not given. When the opacity did not respond to 3 weeks of topical treatment, they were referred to an ocular oncologist for management. Intraoperative records from biopsy were unavailable; use of cryotherapy is unknown. On presentation, the patient had reduced vision OD. On slit-lamp exam, a white plaque in the A/C was seen, obscuring the iris. Given concern for postoperative intraocular cancer spread and extent of disease, enucleation with extended conjunctival excision was done. Gross pathology revealed an A/C mass with a diffuse hazy membrane. Histopathology diagnosed moderately differentiated OSSN with extensive intraocular invasion; a full-thickness limbal defect was visualized. Disease was confined to the globe, without residual conjunctival malignancy. This case emphasizes the importance of taking surgical precaution when excising conjunctival lesions, especially large lesions which obscure ocular anatomy, to maintain scleral integrity and Bowman's layer with limbal lesions. Intraoperative cryotherapy and postoperative chemotherapy should also be employed. If a patient with history of ocular surface malignancy displays symptoms concerning postoperative infection, this case highlights the importance of considering invasive disease.