Why does guy mimic me with stuff, is he into me or super comfortable?

Hi a guy who is work friend, seems to mimic me lots like if I sing song at work he will same song bout 1 minute later, he sits next bank to me.

His body language always kinda towards me, Chris will say randomly "don't get jealous now" and loud so others hear if he talking to another girl usually my friends there?

He came to mine to play cards and he rested his feet against mine but my boyfriend there but he luckily didn't see that, why do this and only to me?
Why does guy mimic me with stuff, is he into me or super comfortable?
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