Minecraft Username:
Fronk_the_Fish

Brief Description:
Swimming/moving in lava, most notably flowing lava, results in the player having glitchy movement.

Instructions:

1. Be in nether(?)
   
2. Drink fire res. potion
   
3. Walk/swim into lava
4. Attempt to escape lava either by walking or jumping/spacebar

How many times did you recreate this?:
Multiple times with multiple locations in the nether.

Result:
Lava can trap a player like quicksand.
Expected Result:
Lava can be swam up and out of, not sucked into.
Evidence: