when i say goal i was rewfering to the part of devouring something after being summoned wich is a primary goal for both(deads|+1 attack;dead|copy), otherway they'll remain a 0 attack creature and with o effects, the rest i said it's just cause one of the primary things that certificate an OP card is that a card is similar but better to another pre-existent card, also this one is of the same element!
This card isn't "better". If you're against a deck of mostly smaller creatures (Fire Queen, RoL/Hope), Otyugh will easily outdo Chasm. Against a deck of mostly larger creatures, it will take Otyugh a while to reach Chasm's potential.
One of Otyugh's strengths is that its presence constantly threatens the opponent out of playing certain creatures. Once Chasm's ability is used, it is gone. In no way, shape, or form is Chasm a "better Otyugh".
The "goal" of Dune Scorpion and Golden Dragon is to deal damage to the opponent. Does that mean that they are too similar? No, it doesn't, because they each fit very different roles in a deck.
Even though they have the same ability, they are not the same card. Another example is Toadfish and Virus. Both inflict poison damage to a creature, but they both do different things. Virus triggers death effects while Toadfish clears enemy lots of creatures.
Here's a thought - let's say I worded the card like this, not actually changing the mechanic in any way:
"0 : Pitfall (Sacrifice Card)
Steal the target enemy creature with lower HP."
Does it still really seem like a "better Otyugh"?