Two-Headed/Mate Question

[Kozuu]

A complicated situation came up last night and I wanted to make sure I had the correct ruling on it.


So here is the situation...

- Plutonium Dragon was Kicked open (20 Bonus PD)
- Ancient +10 was played on Plutonium Dragon (30 Bonus PD)
- Two-Headed was played on Plutonium Dragon (60 Bonus PD)
- Mate was played on Plutonium Dragon (60 Bonus PD and 60 Bonus PD mate, for a 120 Bonus total)
- Polymorph Potion was played on Plutonium Dragon (60 Bonus PD mate remains)

then the confusing part:
- Humongous +10 was played on the mate (+20 from Two-Headed, for an 80 Bonus mate)


The confusion came with whether the remaining mate monster still had Two-Headed affecting it.

I ruled it did since it was a copy of the original and would have copied the Two-Headed effect.

Another player argued that since the original monster with two-headed was removed the effect was removed as well.