"but how do you send 5 headed dragon from your extra deck?"
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Exactly why you shouldn't bother to listen to 🔥s like the TC. This idiot probably had some "idea" which he thought of, but never even tried using for himself.
I can confirm that this combo works, I just used it myself. Cyberdark Claw can indeed send 5-Headed Dragon to the GY. The end result was a 6000+ ATK Cyberdark Dragon.
I also threw in a Release Restraint Wave just before Cyberdark Impact, sacrificing Cyberdark Claw to prevent my opponent from countering my Cyberdark Dragon.
(Apparently, equip monsters in the backrow count as "Equip Spell Cards")