A deck must be assigned a Deck Leader, a specific Monster card that is essentially the duelist's "avatar" on the field
The [On Deletion] effect is activated while treated as [Sukamon], but the name changing effect is lost when the card is deleted and placed in the trash, so you can treat this card as a [Palmon] card
Then Zetalpa deals another 4 damage to it as regular combat damage
It has ruffles of teal fur over its body, including its forked tail and as its membranes
While the Hydra Avatar has gone down a good deal in terms of power - which is really strange to say - it's still a card with a tremendous amount of presence, and hey, it's now Standard legal as well for the next five years thanks to Foundations
Following this rule, I have sleeved exactly three* games over the past fifteen years, with one of those three being an exception to the above rule based on experience