Yōga Sūtra 3.39

बन्धकारणशैथिल्यात्प्रचारसंवेदनाच्च चित्तस्य परशरीरावेशः।

bandhakāraṇaśaithilyātpracārasaṁvēdanācca cittasya paraśarīrāvēśaḥ।

[बन्ध कारण शैथिल्यात् प्रचार संवेदनात् च चित्तस्य पर शरीर आवेशः।
bandha = bondage; kāraṇa = cause of; śaithilyāt = being loosened; pracāra = to the passage; saṁvēdanāt = having sensitivity; ca = and; cittasya = it becomes possible for chitta to; para = others; śarīra = body; āvēśaḥ = enter;]

The cause of bondage being loosened and having sensitivity to the passage, it becomes possible for Chitta to enter other bodies.

Why further dwell into Siddhis? Later additions?