Frogs can kill and eat small slimes with artificially-increased hit points, to the point that frogs deal upwards of 500 hit points' worth of killing in a single lick; and slimes with absurdly high levels of resistance that are similarly difficult to overcome.

Steps to reproduce:

/summon slime ~ ~ ~ {Size:0,Attributes:[{Base:500.0d,Name:"minecraft:generic.max_health"}],Health:500.0f}

 or

/summon slime ~ ~ ~ {ActiveEffects:[{Ambient:0b,ShowIcon:1b,ShowParticles:1b,Duration:2000000,Id:11,Amplifier:40b}]}

Summon frog.

As an added bonus, toggle to survival mode first and attempt to attack the slime, to prove your fist's inferiority to frog.

Outcome: Observe as frog eats slime.

Expected behavior: The slime would survive, or at minimum cause mild indigestion.