The second one blew. A lot.
The first one was a good idea, but not correctly delivered. I would have done it like this:
[ Posted comic does not exist ]
The almost empty second panel provides a dramatic pause to let the situation sink in before delivering the punchline. Your narration wasn't necessary, and the bomb melting part wasn't any good. A bit of work and you could turn out some great stuff though.
Oh, and "I think I'll hammer a nail in my head" comics never funny.
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Dinosaurs had eggs bro, the chicken came way later.