#70 Blood Funnel (Ravnica) Why is it bad
In other words, whenever Blaines Charizard has both Electrode and regular Fire Energy (including cards like Rainbow Energy) attached, the player has can either opt to discard all of their Energy or they can choose to keep one Fire Energy and deal 20 damage less
A good way to approach deckbuilding in a new format, especially one with a fairly limited number of cards, can be to start by looking at what the mana is like and what dual lands or other nonbasic lands are available to you
If you're using a deck with a fast-paced theme set to deliver high amounts of damage fast, like the best Fighting-type deck in the current meta, it can ruin your momentum rather quickly
Take Half-Squirrel, Half- as a great example
Personally i like petan but i could never use him for the reasons i listed above