Established Sunnahs of the Prophet:
Killing the gecko.
Abu Hurairah (may Allah be pleased with him) reported:
The Messenger of Allah (peace and blessings of Allah be upon him) said:
"Whoever kills a gecko with the first strike
will have a hundred good deeds recorded for him;
with the second strike, less than that;
and with the third strike, less than that."
Narrated by Muslim.