Snow layers can break bedrock

If you place a snow layer in the same block space as a ladder, it can destroy any block, including bedrock, in survival.

^{Addition by [Mojang] Mega_Spud (Jay Wells):}
Snow Layers Placed against other non-full blocks will delete the adjacent block also. Tested with:

• Ladders
• Signs
• Item Frames
• Torches
• Skulls
• Flower Pots
• Trapdoors
• Buttons

(You will need to crouch (shift) to place the snow against the interactive blocks)