Fand diese Kreatur auf einer meiner Tomatenpflanzen zusammen mit ein paar Baby -Heuschrecken. Irgendwelche Vorschläge, wie man Heuschrecken loswerden kann?

That looks like a Tobacco Hornworm. Does it have a spine on its tail? It will decimate your tomato plant if that’s what it is. I once pulled like ten off of one plant. If that’s what it is you should check carefully for others.

Edit: to kill them I cut them in half with scissors or gardening shears.

Hornworm. Will destroy a tomato plant in a matter of days. We have an infestation of them in our garden.
Spend some time looking for damage and pull them off the plant by hand (then destroy them in whatever way you please). You can also use a UV or Black Light to find them at night in the dark. They glow bright green and stick out from the rest of the plant.

It’s a parrot larva.