Pete slips the red-k into Clark's pocket to affect him. In previous episodes ("Red") Clark was actually holding the ring and it didn't affect him. But here, separated from him by a couple of layers of flannel, it still affects him.
Please read the following before uploading
Do not upload anything which you do not own or are fully licensed to upload. The images should not contain any sexually explicit content, race hatred material or other offensive symbols or images. Remember: Abuse of the TV.com image system may result in you being banned from uploading images or from the entire site – so, play nice and respect the rules!