Haste Rule 702.10 Glossary

A keyword ability that lets a creature ignore the “summoning sickness” rule. See rule 702.10, “Haste,” and rule 302.6.
Trample Rule 702.19 Glossary

A keyword ability that modifies how a creature assigns combat damage. See rule 702.19, “Trample.”

Rulings (1)

July 15, 2006 Wizards of the Coast
If Lightning Serpent enters without X being paid because an effect puts it onto the battlefield or an effect lets you cast it without paying its mana cost, then X is 0.

Other Printings

Coldsnap (csp)