Sylvan Basilisk

The basilisk ability is deathtouch's awkward cousin: a punishment that only fires on the attack and only when an opponent agrees to it. The trigger keys off being blocked, not off dealing damage, so it resolves during the declare blockers step and kills whatever stepped in the way before combat damage is ever assigned. That makes this strictly an offensive threat, and a curiously social one: nothing happens unless the defender chooses to block, which means the 2/4 frame is really a dare. Send it in, and the opponent either takes two or feeds a creature into the void for nothing. Because the trigger destroys the blocker before damage, the blocker never connects, so the body never needs its toughness to survive that exchange; the 4 toughness matters elsewhere, keeping it standing against burn and ground stalls rather than against the creatures it punishes. On defense the ability does nothing at all; an attacker this creature blocks is perfectly safe. Here is the older, narrower ancestor of the touch-of-death idea, the version that predates deathtouch's reciprocal, damage-based, both-directions templating. This was an era that favored plainspoken full-sentence design, and the basilisk creatures are the clearest record of how Wizards expressed lethal-touch combat before the keyword cleaned it up: a one-way enforcement that only matters when you are swinging and only when your opponent obliges.