Praise be to Allaah.
he can stop his prayer and kill the snake or scorpion, because the Prophet
(peace and blessings of Allaah
be upon him) said: “Kill the two black ones during prayer, the snake
and the scorpion.”
by the authors of Sunan and classed
as saheeh by Ibn Hibbaan).
you can kill it whilst still praying, without moving more than what
is regarded as acceptable, then this is OK and the prayer is still valid.
Allaah is the source of strength. May Allaah bless our Prophet Muhammad
and his family and companions, and grant them peace.